09 May 2021

The Exploding Cost of Grade Separations

Recently, the San Mateo County Transportation Authority prepared a grade separation program update, discussing past and future projects. What immediately jumps out of this document, and others published by Caltrain, is the exploding cost of grade separation projects. The project budgets are shooting through the roof, vastly outpacing inflation. Typical of this cost explosion is the Broadway grade separation in Burlingame, which will grade-separate a single intersection at the eye-watering cost of $327 million.

Cost Modeling of Historical Grade Separation Projects

With the SMCTA slides giving cost data for past and current projects along the Caltrain corridor, it is fairly straightforward to assemble a simple model of grade separation project component costs. All figures are inflated to 2020 dollars before fitting, and we break out unit quantities for each project of the following project components: fully elevated rail over road crossings, split (partially elevated) rail over road crossings, trenched road under rail crossings, pedestrian tunnels, stations, and the number of miles of corridor where the track elevation was changed. With all those quantities broken out for each project, we can fit a simple model that estimates the unit costs by (empirically, not rigorously) minimizing a least-squares fitting residual. The main result of this model is that projects from the mid-1990s through today consistently cost about $36 million per crossing, with not too much variation:


That brings us back to Broadway in Burlingame, which according to this model should cost only a third of the price tag of $327 million. That's right, even including two pedestrian tunnels and a new station, the entire Broadway project should cost no more than $100 million. This factor-of-three discrepancy raises some serious questions about how this project is being engineered, and whether it should even proceed in its current form. One could counter that the cost model presented here is too simplistic and doesn't reflect the unique local conditions of this project, but the model does okay with predicting the cost of every past grade separation project over the last 30 years. Is this a case of over-fitting the data, or have the engineers behind this project simply lost their senses?

With the most traffic of all grade crossings on the peninsula corridor and train-on-car collisions occurring on average once a year, the Broadway crossing is at the top of the state's priority list for grade separation, and we all know that you can't put a price on safety. That makes the Broadway grade separation project ripe for name-your-price taxpayer extortion.

Insane Costs are Baked in to the Caltrain Business Plan

A Caltrain business plan presentation from 2019 attempted to quantify the expense of partially grade-separating the corridor for each contemplated service scenario. The cost modeling for this was even cruder than the simple spreadsheet model described above: the costs for each project were either copied and pasted directly from each city's estimates (of wildly varying quality), or a standard grade separation unit cost of $255 - $355 million per crossing was adopted. This value is up to TEN TIMES the value estimated from past and present grade separation projects, and flies directly in the face of common sense. Despite the coarseness of this spreadsheet costing exercise, the resulting grade separation costs (on the order of ten billion dollars regardless of service scenario) were passed along into the regional Plan Bay Area 2050 exercise.

Why have costs exploded for a project like Broadway, which has proceeded far enough into detailed design to accurately estimate construction cost?

Cost Drivers

Utility relocation. Whenever you dig, surprises happen where utilities buried underground are found elsewhere than expected. The more and deeper you dig, the more surprises you will find. Every new discovery delays or even stops construction work, running up costs. Almost every digging project undertaken by Caltrain runs into this situation. Just in the last couple of years: in South San Francisco, construction of a grade-separated pedestrian access tunnel was delayed for 17 months, at an additional cost of $10 million (and still counting!) due to utility relocation issues. In San Mateo, the 25th Avenue grade separation project, where several new crossings were dug, was delayed by over 500 days due to negotiations with Union Pacific over the relocation of fiber optic cables. Pacific Gas & Electric also had to be paid to move a high pressure gas line. The budget for utility relocation almost tripled, from $12 million to $32 million, not counting the cost of construction delays. Meanwhile, corridor-wide, Caltrain's electrification program (while not a grade separation) is continually digging up their own brand new train control fiber optic cables, which were buried in places that don't match what the contractor said they did. This is causing many months of delay to foundation installation. The matter is now tied up in court, as one of several smoldering side sagas in the big bonfire of litigation over the CBOSS project, still building up to a climactic jury trial in 2022.

Vertical curves made for freight trains. Changing the vertical profile of the tracks, whether up or down, is subject to design constraints on the radius of vertical curves, or how quickly (and over what distance) the slope of the tracks is allowed to change. You might think this issue primarily affects faster passenger trains, but amazingly, the biggest culprit is heavy freight. Freight cars maintained to the bare-minimum standards practiced in the United States can derail at the slightest provocation, so industry track design standards are set extremely conservatively. The maximum vertical acceleration allowable for freight cars is 0.1 ft/s^2, six times less than for passenger trains. At equivalent speeds, the grade change (for example from level track to a one percent slope) must then take place over a distance six times longer than for passenger trains. If you wanted to design the vertical profile of a grade separation to the most aggressive vertical radii and shortest structure lengths allowable for passenger trains, the freight trains would have to be slowed down to 1/sqrt(6) of the passenger train speed to stay under their six times lower vertical acceleration limit. On the peninsula corridor, where we design for 110 mph passenger trains, short grade separations require that the freight trains can't go any faster than 45 mph. Unfortunately, new grade separations such as Broadway in Burlingame or downtown Redwood City are being engineered for 60 mph freight speed, which makes all the vertical curves (and bridges, embankments, trenches, etc.) almost 80% longer than they need to be for 110 mph passenger trains.

Vertical curves that can't overlap bridge spans. Recent preliminary design drawings, such as for the Redwood City grade separations, reveal a new design constraint has been applied that does not appear in older Caltrain engineering standards. The vertical alignments are configured such that wherever the track crosses over a bridge span (as for a grade separation) there is no vertical curvature. To understand how wasteful and silly this is, ask any engineer--never mind, ask any kid: is a train bridge supposed to look like design A or design B, where this  constraint has been applied so no vertical curvature exists where the tracks pass above the under-crossing? Anyone can see this design rule will blow up structure height, length, cubic yards of concrete, and of course cost. And yet, that's what we see in all the profile drawings.

Paint-by-Numbers Structure Depth. There are well-worn preliminary engineering rules for how thick a bridge deck needs to be relative to the loads it must support and the width of a span. Blind application of these rules during preliminary engineering, when the vertical track profile is often decided, results in bridge decks that are comically deep, as measured from soffit (bottom surface of the bridge) to top-of-rail. These massive bridges result in a much higher track profile, needlessly increasing the length, height, visual impact, and cost of grade separation projects. Bridge structural forms exist that minimize structure depth, and it is often possible to shorten spans by adding support columns.

How to build affordable grade separations

Here are some golden rules for designing affordable grade separations. These are rules that are clearly not being followed for Broadway, or for the Menlo Park plans, or for the downtown Redwood City plans, and directly contribute to stratospheric cost estimates for these projects.

  • dig as little as possible. Wherever possible, go up and over.
  • limit freight train speeds to no more than 45 mph.
  • allow bridge decks and vertical curves to co-mingle.
  • from the very beginning, aggressively minimize structure depths.

Another important consideration, in view of the large number of grade separation projects that will be required to advance the decadal process of grade separating the peninsula rail corridor, is to standardize designs. There ought to be a small set of bridge designs that can be repeatedly adapted to each situation, using standard prefabricated structural elements. Not every project needs to be a special snowflake.


  1. How much impact does agency estimated costs for a project, have on the actual amounts bid by contractors?

    For a hypothetical project, the agency gets the estimate high by a factor of 10 and winds up at $1 billion. If a contractor bidding on the project runs the numbers and they would usually bid $100 million for such a project, will they say "Looks like the customer is prepared to pay a lot, so I'll inflate my bid" and bid $150 million? $500 million? $1.1 billion? Or do they bid their best, most competitive offer, figure competitors will also be bidding their best, most competitive offers?

    1. When evaluating bids there is always an “engineer’s estimate” of what it should cost, which is sometimes used to weed out what is considered too low a bid. Advertising astronomical cost numbers such as for Broadway is a form of permission given to prospective bidders to gold plate everything.

  2. Great article as always. Looking at the Palo Alto (endless) discussion of Meadow/Charlston, it seems like Hybrid grade separations are estimated to be 2x less expensive than viaduct, even though both Alma and Meadow/Charlston have to be lowered for the hybrid case. I guess the longer affected segment including shoo-fly for the viaduct out-weighs the extra cost of lowering the roadways. Is this consistent with digging as little as possible to minimize costs?

    Regarding reducing freight speeds, there was a recent Silicon Valley Business Journal article that claimed that UPRR has given up on finding a short line operator for the peninsula and will instead continue to serve peninsula customers itself. This does not bode well for the hope of relaxed specs for freight grade/speed on the peninsula in the future.

  3. The construction industry is seeing huge inflation currently, so the final cost of the Broadway project could go much higher. But at least it will have level-platform boarding, right? Ha ha, just joking....

    1. Not remotely funny.
      Not only no level boarding, but no provision for, ever, either.

      Death is too kind a fate.

  4. The most obvious solution to decrease cost in my opinion is for Caltrain to exempt grades of more than 1%. Going to a 2% or 3% grade will essentially reduce the construction footprint by a half or a third respectfully. This means less property required using eminent domain, less utility relocation, and overall faster construction time.

    Regarding these new grade separations in San Mateo County, all of them should be engineered with a possibility of quad tracking. South San Francisco and Hillsdale/25th Ave should have been designed with quad tracking from the start. Now that they're built, I find it impossible to add passing tracks without demolishing the new center platforms and building side platforms instead. I've seen a schematic of Hilldale that has 2 passing tracks built on a viaduct to the side of the existing station which is the worst design that can be conceived. This means that the passing tracks will have to fly over the existing local tracks, or even worse, cross over them. I fear Broadway will suffer the same fate of being badly designed without any foresight just like SSF and Hillsdale. For $300+ million, I expect it to last forever by future-proofing it. It should be built to easily accommodate 4 tracks.

    I hope the corridor wide grade sep. study that Caltrain will start this year will finally provide a set of standards that will improve cost and constructability of these projects. I think most people want the entire corridor to be grade separated and quad-tracked as it will provide seamless operations between HSR and Caltrain.

    1. While steeper grades sound good in theory, when you engineer your vertical alignment for 60 mph freight trains (which appears to be common practice at Caltrain) the vertical curves have to be incredibly gentle and gradual. For freight trains, a 0.1 ft/s2 vertical acceleration limit at 60 mph results in a minimum vertical curve radius of 23.6 km (yes kilometers!)

      When you have enormous vertical curve radii like this, building up from 0% to a x% grade and then back to 0% (sag and hump curves back to back, with no ramp in between), you get:

      1.0% grade - 7.5 feet altitude change
      1.5% grade - 17.5 feet altitude change
      2.0% grade - 30.8 feet altitude change

      For typical grade separation heights (16 feet road clearance + 4 feet structure depth) you end up with 1.6% being the steepest grade you can plan for without violating the vertical radius constraint or overshooting your desired height.

      This is stupid!

      A typical 20 foot tall grade separation structure would require 5600 feet of length if inappropriately designed for 60 mph freight trains on 1% grades, while it would only require 3800 feet of length for 110 mph passenger trains / 45 mph freight on 2% grades. The key here isn't max grade, it's primarily freight speed and its effect on vertical curve radius. As shown above, you can't even get to 2% without slowing down the freight trains.

      When the rule is that freight trains can only tolerate 1/6 of the vertical acceleration of passenger trains, then you should design for a freight speed of 1/sqrt(6) of the passenger speed. With passenger speed at 110 mph, then freight speed can be no more than 45 mph. Any higher is an expensive waste of scarce grade separation dollars.

      Re: quad tracking, for many years the standard practice in Caltrain's engineering department has been to claim a grade separation design can support four tracks in the future while actually designing the structure to prevent easily adding tracks. Their words and actions have diverged for decades. This is as true of Hillsdale as it is of Broadway and all future grade separation plans where a track alignment has ever been committed to paper, even on a preliminary basis. The engineering / civil works department has never heard of a four-track requirement anywhere at any time, and it evidently just isn't a requirement or design consideration they've ever heard of or worked to. Maybe the business plan folks might finally get through to them, but I wouldn't count on it.

    2. Personally, I think UP should just be bought out of their freight license to run on the corridor. Freight is a losing service on the peninsula anyways. Better to kick UP out so that the Caltrain and HSR can operate full higher/high speed rail later down the line when they finally grade separate everything, but I'll probably dead by the time that happens, if it happens at all.

      MTC Plan Bay Area 2050 did allocate some $7 billion for HSR to purchase ROW and to grade separate a few crossings from Gilroy to Diridon. Since the ROW owner is UP, maybe Caltrain can partner with HSR to demand UP to give up their track rights as part of the negotiations.

  5. I just went and took a look at the new Hillsdale Caltrain station. A complete disaster. The station and almost all access is now oriented away from Hillsdale Boulevard and El Camino, making transfers to buses far more difficult than before. The underpass at the main entrance to the station that would have allowed pedestrians to pass through a parking lot from El Camino has actually been blocked off. If SamTrans buses were rerouted into the new station parking lot, I still don't know how that would work with El Camino and Hillsdale Boulevard Routes. What happened to Multi-modal transport?

    There is a new underpass finishing up at 31st Avenue, but there is not actually a station entrance there! So anyone wanting to get from there to the platform will need to walk quite a distance to the main entrance of the station halfway down the long block. At the 28th Avenue underpass, there is a ramp on one side of the street, stairs on the other. Pedestrians have no way to cross at that point to take the stairs, forcing them onto a ridiculously long ramp or requiring them to jaywalk across the street (which they will do).

    The 31st underpass has wide sidewalks, but no space allocated for bike lanes. This despite 31st Avenue currently being transformed by the city of San Mateo into a shared bike-car connector street. I guess bikes are expected to ride past El Camino on the sidewalk. Fortunately bike lockers are being installed... all the way at the other end of the station parking lot near 31st. I could go on but it is all set in concrete now, so what's the point...

    Anyone else interested in these issues should go visit and see how Caltrain decided to remodel one of their busier stations. It makes San Bruno station look like the peak of transportation planning and design.

  6. Would it cost that much more that say that new stations should be built 4-track-ready? Hillsdale isn't a complete lost cause, as you could build a second island platform if you consume some of the parking spaces making it a transfer station.

    Hayward Park was built with provisions for adding 2 more through-tracks, IIRC, so a 4-track segment is not completely impossible yet.

    1. The marginal costs of future-proofing are small, it's just that someone has to actually care about it. Nobody has any incentive to do it, since it pays more to do it twice than to do it right.

      Hawyard Park has a provision for a third track, by cutting back the southbound platform. There is no room for four tracks without tearing out the platforms and starting over.

    2. Personally I think they should eliminate Hayward Park station if they ever expand to 4 tracks. It is just too close to Hillsdale, especially now that Hillsdale has been moved North.

      Maybe Hayward Park and San Mateo stations can be merged to a new 4-track station at 9th Ave? It might simplify future grade separation in San Mateo which are complicated by the narrow ROW.

    3. Agreed about Hayward Park, the station spacing (and ridership) don't justify its continued existence as a Caltrain Station.

    4. You would think that with Prop 1A money helping fund Hillsdale that it would be built as a 4 track station from the start. I also agree with closing Hayward Park to easily 4 track the segment.

    5. Agreed about Hayward Park, Atherton (done!), College Park AND Broadway.

  7. It was pointed out to me that one of the key reasons for the astronomical cost of the Broadway project is that it includes 3.5 acres of roads and sidewalks that will be lowered, resulting in 3.5 acres of utility relocation. Raising the tracks another few feet would take care of this problem, although it is more likely that scarce grade separation monies will instead be used to assist the City of Burlingame's public works budget with 3.5 acres of new pavement and new utilities.

    It's a perfectly logically crafted story: CP Trousdale to the north "constrains" the length of the grade separation structure, which combined with 60 mph freight speed and 1% grade design rules "prevent" the structure from being sufficiently elevated over Broadway, which in turn "requires" 3.5 acres of utilities to be relocated and 3.5 acres of roads and sidewalks to be rebuilt.

    1. "It's a perfectly logically crafted story: CP Trousdale to the north "constrains" the length of the grade separation structure, which combined with 60 mph freight speed and 1% grade design rules "prevent" the structure from being sufficiently elevated over Broadway, which in turn "requires" ..."

      It's also a story that is laughably, insultingly fraudulent.
      No question about it: Caltrain's staff and Caltrain's perm-temp consultant mafia are simply outright lying. Their sole priorities are cost maximization and self-enrichment.

      This is simplest second grader arithmetic.


      * Northern match point of their service-destroying, budget-exploding Broadway scam project into existing tracks is at +0.1534% grade and 860+ feet (feet! in 2021!) clear of the Sacred Crossover of CP Trousdale.

      * Southern match at grade +0.6031% (again rising to the south) 350+ feet north of the inexplicably-out-of-scope Oak Grove Avenue grade crossing.

      Because we're masochists we're going to play by the cost-maximizing "design" "standards" Caltrain's consultants are "forced" into. In fact, we're going to use exactly the existing grades of the Caltrain scam, and use the same 60mph AREMA freight vertical curves (even though the freight speed everywhere on Caltrain is ≤50mph and even through recent Caltrain projects in San Bruno and San Mateo have sub-45mph vertical curves), and use the same scam 1% grade "limit" (though Caltrain's recent San Bruno project exceeds this), and use the same over-the-top stream-train-compatible Caltrain bridge depth. We're also going with Caltrain's insane "standard" of no vertical curves within 100 feet of a platform (this truly makes zero sense.)

      OK! Now ... a solution!

      A) Move the start of the northern grade 500 feet north. (NB Everything's roughly similar varying this from 420 to 600 feet.)

      Note this is 360+ safe feet from The Holiest of Holy Crossovers of CP Trousdale, all abase yourselves before CP Trousdale, amen.

      This 500 feet of extra run buys 4.23 feet of elevation (recall +1.0000% - +0.1534%)

      B) Move the end of the northern grade 127 feet south.

      Note this is still 150+ feet from the platform as "designed" by Caltrain.

      This extra run buys another 1.27 feet of elevation.

      Oh look! We're now 5.5 feet higher than Caltrain's "design". FREE AND CLEAR!

      ONE GUESS how deeply they "need" to excavate Broadway, California Drive and Carolan Avenue for their $330+ million road-reconstruction and utility-relocation pork-fest!

      C) Move the platform north end 50 feet north.

      D) Raise platform to 760mm ATOR for level boarding, which would be the standard if Caltrain weren't run by chimps.

      E) Extend platform by 110 feet (ie 300m long platform, ie 2x150m = 2x6-"car" coupled trains, ie what should be the shortest platform on the line, not the 700 feet or 875 feet or whatever the chimps pull out of their rear ends this month.)

      F) Start downgrade vertical curve 88 feet further north.

      Note this is 100 pointless feet clear of 300m platform.

      This buys 0.88 feet of the 5.5 feet we need to lose.

      G) End downward grade 288 feet further south.

      Note this is about 60 feet from Oak Grove, but there's no geometrical or rail dynamic or rail maintenance reason to object to this.

      This buys the remaining 4.62 vertical feet needed (at -1.0000% - +0.6031%)

      DONE. We CAN get over Broadway without "fatal impact" to CP Trousdale.

      So yeah, looks like Caltrain staff and Caltrain's perma-temp consultant mafia are lying about "needing" to excavate.

      Who'd have guessed?

      I mean, with $330 million and rocketing upwards at stake, who'd POSSIBLY IMAGE anybody would lie through their teeth in order to maximize public-private wealth transfer?

      I mean, it's not like this has ever happened before, right?

      The grift is the point. Grift is the only point.

    2. "one of the key reasons for the astronomical cost of the Broadway project is that it includes 3.5 acres of roads and sidewalks that will be lowered, resulting in 3.5 acres of utility relocation. Raising the tracks another few feet would take care of this problem, although it is more likely that scarce grade separation monies will instead be used to assist the City of Burlingame's public works budget with 3.5 acres of new pavement and new utilities."

      The First Law of Holes is "Stop digging!"

    3. I do tend to agree that Broadway is a "set money on fire" project, and is allowed to be so because you can't put a price on safety.

      One nit: the level boarding height you seek is 550 mm, not 760

    4. Correction: the level boarding height you seek is 1219mm (4 ft).

      There are more rail vehicles (and rail passengers) in use between DC and Boston than the rest of the country combined, and there will remain so for the foreseeable future. All of them use a 4 ft platform. This is the de facto standard and there is no need to use a new boarding height for as small a system in vehicles or riders as Caltrain. That is unnecessary exceptionalism of the kind rightfully skewered on this blog in other subjects (CBOSS vs ETCS, etc.)

      For heavy rail passenger vehicles in N. America the standard should be:
      Standard gauge, AAR Plate C, 3.2m width (10'6"), 1.219m platform (4'), 25m car length*, 25kV 60Hz catenary.

      Any manufacturer making a trainset capable of service on the NEC or the New Haven line should know that they can sell that equipment to any service in the country. Congress should make these requirements statutory and refuse to fund projects that don't meet them, while offering extra funding to bring non-compliant systems into spec (looking at you SEPTA with your 12.5kv 60Hz *AND* 12.5kV 25Hz wire, or you MTA and LIRR with your top v bottom third rail shoes).

      Clem, I believe you are a fan of 550mm because of how it interfaces with the lower level of bi-level cars, but the busiest systems in the country use single level equipment exclusively. With a 400m train box at Transbay and electrification here, there is no reason Caltrain cannot move more people with single level cars, using longer more frequent trains. Even if you want bi-levels for some reason, a busier system still (RER A in Paris) uses them with high platform boarding. HSR trainsets are almost guaranteed to be single level high platform, and there is no reason that HSR trains and Caltrain shouldn't be able to share platforms.

      *Richard, you are correct about using EMUs not individual cars, but as a practical matter everyone refers to "units" as cars, and it is still necessary to define the length of each rigid chassis, whether permanently coupled or not.

    5. In terms of HSR, level boarding tends to be 50-51 inches. This is the standard for HSR systems that use Shinkansen technologies such as Japan, China, Taiwan, and soon to be Indonesia, Thailand, and India. Even Spain uses Shinkansen platforms. I believe most HSR networks in Europe (TGV, DB, Italy) do not have level boarding.

      I heard that if level boarding were to be implemented with the current Caltrain standard of 5'5" from the center of the track to platform edge, freight cars would potentially strike the platform. If this is the case, then Caltrain should of bought the wider version of the KISS. The wider KISS would give Caltrain more capacity with 3+2 seating instead of the current 2+2. The wider KISS has a similar loading gauge to the Shinkansen which gives HSR more flexibility to potentially build in-fill stations on the Peninsula.

  8. I understand how 1% vs 2% might affect grades, but how does vertical curve radius to transition between 0% and 1-2% has an impact on speed of freight? If a 110mph passenger train won't become airborne at the vertical curvature transition, then a 60mph freight won't either.

    1. Nothing becomes airborne anywhere. The difference is passenger trains are allowed up to 0.6 ft/s^2 of vertical acceleration while freight trains are only allowed 0.1 ft/s^2.

      If a 110 mph passenger train pulls 0.6 ft/s^2 on a vertical curve, then a 60 mph freight train on the same curve will pull 0.18 ft/s^2, in violation of the six times lower freight limit.

      For the freight train limit to be met, the freight train must travel no faster than 1/sqrt(6) * 110 mph = 45 mph

      Does that help explain it?

    2. Makes sense. I didn't realize there's standard of .1/.6 ft/s^2 for vertical acceleration.

      Are you aware of any waivers of this limit for straight track? Seems like even .2 ft/s^2 would be a big savings at low risk.

    3. @Clem, the freight speed is just as excessive as their maximum acceleration. Slowing it down to completely reasonable 50 mph for a branch line would shorten vertical curves to (5/6)² = 69 % of what is currently required.

      Also when looking for this, I stumbled upon an oldish recommendation to keep vertical radii for trains with standees greater than 0.77V² [m, km/h] which should translate to 0.1 m/s² or 0.328 ft/s² but couldn't find in in my (less old) copy of actual track geometry requirements (it sets minimum radius of 0.4V² [m, km/h] that translates to 0.63 ft/s² and exceptional radius of 0.25V² translating to exceptional acceleration of 1 ft/s²).

    4. "Also when looking for this, I stumbled upon an oldish recommendation to keep vertical radii for trains with standees greater than 0.77V² [m, km/h] which should translate to 0.1 m/s² or 0.328 ft/s² ..."

      I suspect this was European Norm 13803 "Railway applications - Track - Track alignment design parameters - Track gauges 1435 mm and wider" section 5.2.11:

      5.2.11 Radius of vertical curve R_v

      The normal limit for radius of vertical curve is $R_{v,lim} = q_{R,lim} \cdot V^2$ [m], where $q_{R,lim} = 0.35 m \cdot h^2/{km}^2$, without going under 2000 m vertical radius.

      NOTE 1: On lines where most of the passengers may be standing, it is recommended that $q_R$ should be greater than $0.77 m \cdot h^2/{km}^2$.

      The exceptional limit for radius of vertical curve is $R_{v,lim} = q_{R,lim} \cdot V^2$ [m], where $q_{R,lim} = \cdot h^2/{km}^2$ for hollow [ie "sags", "Kuppen"], and $q_{R,lim} = 0.16 h^2/{km}^2$ for crests [ie "Wannen"].

      For sections with switches and crossings laid in vertical curves, the limits defined in EN 13803-2 shall be complied with.

      "but couldn't find in in my (less old) copy of actual track geometry requirements (it sets minimum radius of 0.4V² [m, km/h] that translates to 0.63 ft/s² and exceptional radius of 0.25V² translating to exceptional acceleration of 1 ft/s²)."

      That's the current as far as I know in advanced industrial democratic parts of the world, eg German RiL 800.0110

      Note that the AREMA (North American club for boys who are fans of derailment, steam locomotives, slugs, kips and furlongs) passenger only vertical radius of 0.4217 V^2 [m, km] which isn't horribly worse ("only" 5.5% more space wasted on vertical curves) than 0.4 V^2. It's the AREMA freight 2.53 V^2 which is murderous.

  9. Off topic, but I would be curious if Clem has any thoughts on the Link 21 plan put out by a group of local transit agencies. It covers a series of projects, mostly heavy/mainline rail, throughout the greater Northern California region (Bay Area to Sac) and was recently profiled in SF Weekly:



    Some of the projects relate to Caltrain or other things mentioned on this blog (DTX, Dumbarton, Altamont, Caltrain to Salinas(!)) while others are more expansive (2nd Transbay tube, electrification of Capitol Corridor, SMART, etc.)

    1. The design of DTX has to be changed if it is to connect to Link21. The current alignment of DTX does not allow for a full 16-car HSR train to fit inside Salesforce without an expensive and unnecessary train box extension. This extension will then take away valuable real-estate required for the throat of the Link21 tunnel to descend under the bay without the need to punch a hole though the sea wall.

      Here is a Youtube link to a proposed alignment of DTX done some time ago.

      Salesforce is over 1500 ft long meaning the train box is more than adequate enough to store a full 16-car train. The alignment above utilizes the entire length of the already built train box without the need of an extension. No tight curves, unlike the current alignment.

      Here are some of my thoughts on how to improve the alignment above:
      1. Use a single large Tunnel Boring Machine instead of two smaller ones. I personally think that a 50 ft diameter TBM would be sufficient. A large 50+ ft diameter tunnel can be split into two levels meaning 4 tracks (2 tracks per level). Although this may not be fully beneficial to DTX, unless there are plans to add another train level to Salesforce making it a 12 track, 6 platform station, it will be beneficial to Link21 as standard gauge trains (HSR, Caltrain, Capitol) can use the upper level while broad gauge Bart trains can use the lower level. Furthermore, VTA is going to use a large single bore TBM for Bart in San Jose. Using a single large-bore TBM and sharing it with these 3 projects can save costs.
      (I personally would love to have a 12 track Salesforce where Caltrain and Capitol Corridor will take the first 6 tracks and HSR will take the 6 tracks on the lower level but that would never happen)

      2. With the use of a single large bore (50+ ft) TBM, the above alignment can be refined a bit. The entire alignment will go from tunnel 2, under Pennsylvania to 7th. From 7th, the tunnel will have a single curve transitioning to Howard (Not 3 tight 90deg, 30mph curves like current alignment). From Howard, I would begin transitioning to Salesforce from New Montgomery, using a portion of the already built Salesforce train box throat (not all). The Youtube alignment is constrained in the fact that it does not use eminent domain. I think eminent domain would lessen the complexity so I would condemn a few buildings. The above alignment also has the platforms at Salesforce to be straight, but I would have a gentle curve to the platform, using a portion of the Salesforce throat. Japanese Shinkansen uses curved platforms while still being ADA compliant so why can't we. A great example is Tokyo station. If you look at an aerial image of Tokyo station, 3 out of 5 of the Shinkansen platforms are curved in a similar manner to how I would propose using the existing train-box and part of the throat (Tokyo Shinkansen platforms can fit 17-car trains).

    2. In my opinion Link21 and DTX would never be separate projects in any reasonable universe. The EIR and design for DTX are so crusty (going on 20 years) that the "purpose and need" is effectively overcome by events since the late 1990s when the project was set in motion. My opinion is that it's okay to tear up the DTX plans and start over, merging the project into Link21, even if it costs another ten years of delay.

      The new requirements should be:
      - standard gauge + BART in a four-track bored tunnel under the Bay
      - through running at Transbay train box, including having Caltrans dismantle a few high rises to clear the necessary tunnel right of way to the Bay
      - Caltrain storage / maintenance yard in the East Bay

      The absolute worst and most expensive outcome for taxpayers and riders, not coincidentally the one that is being steered towards as far as I can tell, is DTX built as-is (as a stub) and a new Transbay tunnel built for BART only.

      The Link21 tunnel itself is not going to be that expensive (there is no magic in bored tunneling), it's all the other stuff getting layered onto it on both ends that really starts to add up.

    3. @Clem
      Judging from the recent ESC meeting that took place on 5/21/21, the Interim Project Director, Stephen Polechronis, is very reluctant to deviate from the current scope of DTX. He wants to quickly get the project moving for federal funding. Roland Lebrun who proposed the 7th street PAX/DTX alignment from the Youtube video listed has been continuously voicing support to rethink the alignment for several years now. Stephen Polechronis and the ESC board have repeatly shot Roland's idea down.

      This is a PPT from the latest ESC meeting for operations of DTX:

      In this PPT, they admit that there are concerns with the current build-out of DTX and its compatibility towards a future Link21 connection (slide 9). They can't be this short sighted. They even changed the platform arrangement from 1 dedicated Caltrain, 2 dedicated HSR to now 2 dedicated Caltrain and 1 dedicated HSR.

      Quite frankly, it is important to get such an important, transformative mega-project right the first time around. The ESC board should not be afraid of potentially restarting from scratch. They are the ones putting pressure on themselves to get this done quickly. As far as the public is concern, we want DTX to be built CORRECTLY. There is already some $3+ billion that is already allocated or will be allocated towards this. We should build it right so we don't have to rebuild later on.

      The PAX, DTX (7th st alignment or some variant of it), and Link21 should be bundled together into a single project. This would maximize public support, maximize technical engineering expertise, and minimize costs.

    4. At least they acknowledge the existence of Link21. You don’t need detailed assumptions or simulations to know that a through station performs much better than a stub terminal, especially in this age of PTC software initialization delays.

      I worry that DTX is firmly entrenched in the fallacy of sunk cost and bureaucratic self-preservation. You can’t get anyone to understand a different approach to the problem when their salary depends on them not understanding it.

      PAX is the most horrifically expensive grade separation ever conceived, far worse than Burlingame’s Broadway.

      Incidentally, the transportation industrial complex profits handsomely from building things wrong. Why build it right when you can build it twice and get paid for it again?

    5. I agree that PAX is indeed quite unnecessary. Two relatively simple grade separations would be cheaper than boring a 1+ mile tunnel. The thing is that the city and the land owner, Prologis, wants Caltrain to vacate 4th and King for development. I only include PAX as that would allow the city to plan for whatever it wants to do with 4th and King.

      My only gripe is that DTX is being planned without considerations for others (such as Link21) and for future needs. If the TJPA and the city had the foresight to vacate 4th and King when designing Salesforce, I guarantee you that the train box would be built deeper to accommodate more train levels. Even HSR in the beginning demanded its own dedicated train level before capitulating. It would of cost a couple hundred million to build the extra rail capacity in the early 2010's, I can't even imagine how much it would cost now that the thing is already built. Probably billions.

      Quite frankly, I would rather an entity like MTC take charge of DTX/PAX because at least they have the mindset that this project is a transformative regional project and not just something that allows people to save 5 minutes of walking to their work. MTC's representative on the ESC was the only one in my opinion to voice some concern with DTX's future compatibility with Link21. Although I doubt that anything will change.

    6. What the hell is "PAX"?

    7. If I remember and parse correctly, PAX is shorthand for the recently-selected Pennsylvania St. tunnel approach from Potrero Hill under 7th/Mariposa/280 to (but under and alongside) the current SF Caltrain depot.

    8. ^^ Correct. PAX stands for Pennsylvania Avenue Extension. It connects the DTX to the unused second tunnel bore of Tunnel #2. If the PAX were to be built, then 22nd station will have to move to the entrance of Tunnel #2 (between 25th and Cesar Chavez).

    9. OK so "Anonymous" here is Roland Lebrun.
      Don't be coy! You're not fooling anybody, no more than I ever could, so don't try -- it just confuses conversations to have multiple anonyms hanging about.

    10. Sorry. I'm new to commenting on blogs so I didn't know how to work the name. I'm not a genius, just a passionate railfan. I do attend some meetings from Caltrain and TJPA which is where I heard some of Roland's ideas, but rest assured I am not him. I think I and Roland have a differing opinions when it comes to HSR. From what I gathered, he supports implementing a TGV or European style system while I am firmly in the opinion that we should implement a Japanese style Shinkansen system. I have ridden on both Europe's best EMU, a Siemens Velaro variant, and the N700A Shinkansen. I believe that the Japanese product is far superior (more quite and more comfortable).

      The Shinkansen is 11 ft wide with 3+2 seating for standard class and 2+2 for green class which means the seat width is super wide. Seats swivel 180deg meaning that you are always forward facing. Each row has its own windows. 3+2 seating means more capacity which equals more profits. Aerodynamic nose means no tunnel boom. Bogie wheel covers, flush diaphragm covers, aerodynamic single pantograph arm with pantograph winglets, and aerodynamic pantograph housing fencing reduces noise pollution to the people living near its operation. A pressurized cabin with plug doors means less ear popping when going through tunnels. Fully active suspension means stable running even through the bends at high speeds. From CAHSR's own documentation, the Shinkansen has the most capacity while being the most powerful and the most energy efficient per seat.

      It almost sounds like a sales pitch but I truly believe that we should learn from the best. Not to knock on Alstom or Siemens but the Shinkansen is still the best and most highly developed HSR system in the world. JR Central just released the N700S which uses lithium ion batteries to power the train at slow speeds in the event of an earthquake in which ATC/ATP automatically cuts power to the catenary. This would allow the train to cruise to the nearest station. Further more, JR East is currently testing the ALFA-X, a train that is to be debuted in late 2020's, early 2030's (perfect time for CAHSR). The ALFA-X has 2 different noses (one is 16m long while the other is 22m) and 2 different style pantographs to test out noise pollution. The train is regularly testing at 400 kph (250 mph), which is astonishing given the fact that the track is limited to 205 mph due to noise. The ALFA-X also implemented and air brake system, similar to the ones on an airplane.

      Link of the air-brake system:

      Bottom line is that I want our technologically advanced state to have the best technologically advanced system in the world.

  10. Hey if there's somebody who has any skill with browser Javascript UI and would like to help me out with some code (to generate and display vertical alignments of Caltrain) please get in touch mly@pobox.com . Anything UI related is impossible for me, Javascript makes me stabby, and d3.js is a black box of terror. It ought to be trivial for somebody who knows what they're doing, but I've hit several walls.

    Oh and if anybody has something (not a "web service", just some code) that even remotely reliably turns basic SVG (that I generate using the aforementioned Javascript horrors eg Broadway-fully-elevated-profiles.svg) into acceptable PDF I'd like to know of it.

    1. For the last, try Adobe Illustrator… (not verified, however).

    2. Thanks, but I was looking for code that works that I can use in a program.
      (My legitimate fully-paid-for copy of Illustrator stopped working years ago, taking decades of pointless drawings with it. And no, I'm not paying to rent it. And no, I'm too burned out to write a PDF library myself to do this ... again, for the nth time in three decades.)

      I've managed to work around enough of the bugs in the Affinity Designer MacOS program that I can read in SVGs and spit out PDFs without infinite pain, but again this wasn't the point. I don't want to drive mice around and manually correct lots of application-specific bugs.

      The point, if there is one, is that SVG data, though "native" to kewl modern web browsers, is just a pain to view! I want to just put a file out there, no matter how tall or wide, and have people able to pan and zoom and scroll through it in the obvious UI manner. Sadly "non-native" PDF is supported better in browsers for this basic basic basic stuff.

      It would be nice if I had some way to turn on and off "layers", and to zoom directly to pre-designated "views", (or, how I optimistically started out, click-and-drag to reposition and recalculate and realign) but yeah, here's a big-ol' SVG file chock-full of data that nobody will look at or care about. Hours of life, gone. Poof!

    3. Nice SVG file. I sent a rough draft Illustrator PDF in your in-box... but it doesn't quite answer your question or needs. Much info opened up fine; a bit did not (like your vertical pale red bars). Type was super-small, mostly possible to enlarge. Broke it into layers corresponding to the grouped notes and linework.

      It may take "eye of newt" AND "wing of bat..." some sort of PDF-running app, for a reader to be able to toggle layers (other than by opening the PDF in Acrobat and playing with layers manually) Particularly as it takes a couple layers to show certain combinations of bypasses or overcrossings. I guess one could duplicate and lump the layers into 3 combo layers for Redwood City-Atherton, covering each complete kerfuffle, making a few less layers to play with. Roll-over graphics are another (possibly bygone) web solution, which Illustrator doesn't know squat about. (Or more specfically, I don't, plus I find them a bit annoying).

    4. Thanks you so much for this Richard. The SVG displays fine for me in Chrome. As far as SVG zoom/pan with javascript, a quick google search came up with this which looks promising: SVGpan

      One thing I noticed in your SVG is that the existing grades around Diridon Station seem to make it impossible to elevate the station as SJ dreams of doing with their Diridon Integrated Concept plan (DISC)

      I would love to hear what you think is a reasonable approach for a future Diridon plan, assuming HSR goes ahead with Pacheco. Given the constraints of Los Gatos Creek and the existing freight spurs both north and south of the station, it seems to me that elevating the station is a pipe dream.

    5. "I would love to hear what you think is a reasonable approach for a future Diridon plan"

      The same thing I think about anything involving San Jose, Capital of Silicon Valley, or anything involving SPUR, or anything involving Visioning Exercises with Stakeholders: I say we take off and nuke the entire site from orbit. It's the only way to be sure.

      It's game over in SJ anyway. Whoever even considered, let allow actively promoted any non-rail construction or development anywhere inside (to the west of) the curve north of the SJ Cahill Street station needs to be crucified. Not just figuratively. Whatever other bullshit games they play with Integrated Concept Community Process is just pissing on dumpsters full of cash on fire.

      Hey, but if the certified assholes (Parsons Transportation Group foremost, Caltrain, CHSRA, SFCTA, TJPA, etc) can erect structural columns exactly where the trains need to go and exactly where human access to platforms needs to go in big bad old mean San Francisco, then GOD DAMN IT, San Jose, the little town with the biggest inferiority complex in the universe, is going to do it's very very tiny fists of rage bestest to do just the same. Look, we're a big city! We can be as corrupt as Willie Brown! Just watch us! We're the Capital of Silicon Valley. We can be corrupterererer! VTA is even worse than Muni! Diridon Pangalactic can and will be worse than Transbay Clusterfuck! Our BART line is 1000000 times worse than yours, and even 50 times worse than your Central Subway. San Jose can do it!

      I have had some thoughts about how this could have been done. But I'm not planning to hijack this thread because it's pointless pointless pointless.

      (Yes, tracks and platforms should be elevated above existing grade.
      Absolutely no no no no not ever should there be separate HSR in the sky and ghetto Caltrain stations.
      No no no should there be separate HSR and Caltrain platforms.
      No no no should anything anywhere on the line be configured with HSR/express tracks in the middle, as allowingCaltrain turnbacks is mandatory.
      Anybody who even mentions "concourse" or "gateway" or "waiting room" or "grand entrance" or "baggage" or "ticketed area" or "landmark" or "security zone" or "back of house functions" needs to be shot. Just taken out and shot.
      San Carlos Avenue goes under the tracks.
      It's worth thinking about putting FRA freight crap (including Amtrak, not that that matters, on the western side, with the real actually useful trains elevated and using some steep grade bumps to fly over. I think it can be done.
      Everybody responsible for CEMOF should be shot. I said that since 2002, and it's still true, and I'm still right. Getting trains to and from this turkey is a nightmare, even with 2.5% grades, because there's all sort of conflicting traffic, including freight.
      VTA "light rail" should be put out of our misery.
      Freight line to Vasona doesn't matter, can be bought out, and put out of our misery.
      And ... wait for it ... the various elevated proposals south of the station (whether crazy high along 280 or something a bit more reasonable paralleling the existing snakey at-grade line) ... are not insane, in concept. Yes, insane at any level below that, but there are ideas there worth thinking about, and value engineering the hell out of.)

    6. Thanks for the viewpoints Richard. Having lived in both SF and SJ I find that SJ government is less outright corrupt than SF but unfortunately even more inept and prone to exploitation by consultants.

      I was hopeful about the DISC project when they chose the Dutch consultants Arcadis as I thought they would provide an international sanity check, but no sign of that so far.

      The frustration I have is that it is still early enough in the process to advocate for a sensible and cost-effective approach and actually have an impact. However, there are so many complex constraints that I have difficulty imagining what that solution would look like.

    7. I think the biggest tragedy in San Jose is where they put CEMOF. I believe HNTB was the company that designed CEMOF, but I'm not entirely sure. If they were though, then they should be shot. Who would put a facility in a location where you can have a straight track. The main trunk line now has a massive reverse curve just to go around CEMOF.

      Part of the Diridon concept plan is that they are now looking at moving CEMOF. If CEMOF and the current main line had been designed with its current location swapped in the first place, then we wouldn't need to spend millions to do it in the future.

      Regarding Diridon itself, I believe there will be no passing track as every HSR train will stop at San Jose. I also believe that there will not be any need for baggage as the interior concept drawing of the HSR train is similar to that of the Shinkansen. The Shinkansen allows you to bring carry-on luggage. There is no check-in luggage system there. Just for reference, I had a 3 large, overweight suitcases with me while traveling and in Japan and it fit over the rack, although just barely. For now, there doesn't seem to be a massive concourse designed but I wouldn't be surprised if it were to pop up later as a concourse would allow for rent to be collected from potential shops and restaurants. Another decision that will likely happen is that HSR will most likely have dedicated platforms. Caltrain is nowhere in terms of level boarding. HSR will also most likely have faregates and paid areas. Justification for this is because they need to run without a subsidy, so they need to weed out non-paying passengers. I think security is a nonstarter when it comes to HSR. China and Spain are the only places I know where you need to go through a security checkpoint for HSR. The whole point of HSR is that it is more convenient than a plane.

    8. jpk122s: I don't have great survey data on the elevations around the "downtown" SJ station, but looking at it roughly, the biggest (self-imposed, self-inflicted) vertical "constraint" is the freight connection to the Warm Springs line, ie the southern leg of the freight wye just south of CEMOF.

      Even with (self-imposed, self-inflicted, rent-seeking) steam freight "constraints" of 1% grades etc, it isn't a struggle to rise from the existing Caltrain grade elevation north of CEMOF (ie starting somewhere around the West Taylor Street rail overpass) to a level and 420+m long flat station platform section above the present station site.

      And by going with perfectly-normal-elsewhere 2.5% grade it's even easy to go from the existing awful CEMOF site up to the platform level.
      (And with a combination of a short-and-steep CEMOF access line and a bit of a upwards bump in the mainline, it's even feasible on paper to get to and from CEMOF without conflicting the mainline tracks, instead diving under.)

      (I extracted this http://www.pobox.com/users/mly/caltrain-hsr.blogspot.com/vertical-profiles/San-Jose.svg for you from my larger ongoing crayonic but pretty-damned-accurate line profile.)

      Aside from that extremely marginal freight connection, and the totally marginal "Vasona" freight connection, getting all the trains and tracks over Santa Clara Street etc is "just" a matter of throwing infinite money and concrete at the sort of people who love absconding with infinite amounts of public money.

      But again, this is pretty much irrelevant the "Google Campus" thing -- just approved by the Far Sighted City of San Jose, Capital of Silicon Valley -- really is GAME OVER for Caltrain and HSR in SJ. Where any fool can immediately see you need to put tracks, and where there's nothing but industrial wasteland today? Gone.

      Take a few tens of millions in developer fees, spend tens of BILLIONS to work around the problems caused. Hey, but they say it's "transit oriented" so it must be good, right?

      (Same shit in SF with Transbay -- the kickbackers of Willie Brown who "won" "architectural" "design" "competition" for the bus station in the sky and a 100%-recycled Hong Kong office tower clone with their clinching $100 million sweetener offer for the tower site immediately sucked back the $100 million and more in "architectural" "services". We'd be $2 billion ahead, and without a literally disastrous and very permanent impediment to rail service, if everybody involved had simply dropped dead instead.)

    9. Quite frankly, Caltrain governance changes can not come soon enough. I am in full support with a merger with BART or HSR. They have the staff and technical knowledge necessary to design a RAILWAY. Sure they don't have the best record, but it sure is more than what Caltrain is doing right now. Caltrain needs to think long term and future proofing instead of meeting the needs of yesteryear (ie. San Bruno grade separation, SSF station, Hillsdale grade separation).

    10. I don't think you have any idea at all about how deeply the rot extends, and the fact that it is the exactly same crew of unprofessional, unethical, sub-human, unqulaified consultants who run the show, regardless of the "governance" lipstick on the pig.

      Pacheco? PBQD (now WSP) consultants, running up tens of billions of dollars for their own direct profit. Also, got to appoint one of their own VP's as the CEO of the pubic" CHSRA agency.

      Palmdale? PBQD (now WSP) consultants, running up tens of billions of dollars for their own direct profit. Also, got to appoint one of their own VP's as the CEO of the pubic" CHSRA agency.

      BART to Warm Spring? PBQD.
      BART to Berryessa? PBQD.
      No HSR to Fremont? PBQD.
      No meaningful SJ-Fremont rail service for the last three decades? PQDB.

      BART to Millbrae, totally and completely fucking over Caltrain service, while directly enhancing private profit? PBQD and Bechtel

      Central Subway in SF? PBQD.

      Transbay Terminal? The usual suspects. PTG especially deserves execution, but they all, including your would-be railway experts and saviours at "CSHRA", approved and promoted this minimally-$4 billion (more likely $6 billion in the end) catastophe.

      The scum who control capital projects at "BART or HSR" have far far far far far less than "technical knowledge necessary to design a RAILWAY".
      The are the same cast of self-serving criminals who produce the wrong outcomes (wrong public outcomes, not that anybody cares) at every other agency.

      Only mass firings and criminal charges could possibly change anything.

      Speaking of which, anybody remember that a quarter of billion dollars disappeared into CBOSS and ... well ... nobody lost a day's sleep, a promotion (to Caltrain CEO, even!), a dollar fine, or a year in prison? Nah, nobody did. Let's look to the future! Buy American Caltrain Electrification is going just great!

      Same house, same call.

      I've direct personal experience of the breathtaking ignorance, Dunning-Kruger obliviousness, professional incompetence, and sub-basement ethicality of these people. Putting a different set of puppets "in charge" of rubber-stamping their criminality is just fine with them. Just fine. It's happened before, it may happen again, but the cash will just keep flowing their way until there are actual criminal prosecutions. Good luck.

    11. I see your point. It kind of glossed over me that Parsons merged with WSP some time ago. Funny how brand perception can change with name changes (ie Comcast and Xfinity). WSP has a history of public works that have gone way over budget. Their contract as a rail delivery partner will be expiring soon and I hope that it doesn't get renewed. Bechtel comes to mind as a replacement and they have built large infrastructure before like the Channel Tunnel/ HS1, but they also have their fair share of cost overruns.

  11. I have two questions regarding the engineering of bridge structure for grade separations:
    1) Besides Caltrain's standard saying so (and Caltrain being lazy), what are the reasons why Caltrain's standard prohibits vertical curves on the bridge spans or platform? Are there any scientific/engineering reasons specific to North America or Caltrain as there are roadway bridges with vertical curves right in the middle of the bridge span and passenger rail station with vertical curve right in the middle of the platforms in other parts of the world?

    2) To reduce the structural depth of the bridge to "U-shaped grade separation level" without kicking the heavy freight out of the Caltrain corridor (I know someone should kick them out, but it seems like not many people has guts to poke freight railroads...), how short the span need to be? Can the bridge over Broadway in Burlingame (100 to 110 ft. long based on Google Earth) be built with only one column at median and still accommodate heavy freight?

    1. Regarding the first question, I have no evidence that design standards dictate any such restriction. It’s just that finished profile drawings have this feature. Not sure how that particular sausage got made.

      The other question I’m not sure about as I am not a structural engineer.

    2. "Can the bridge over Broadway in Burlingame (100 to 110 ft. long based on Google Earth) be built with only one column at median and still accommodate heavy freight?"

      Caltrain's design for Broadway is a 147.5 foot (44.933m) bridge of two approximately-equal spans (longest of the four spans 23.635m) supposed by 5.5 foot deep cast concrete box girders (longest girder 77.33feet 23.571m) over seven -- count 'em SEVEN -- sweet sweet sweet traffic lanes. It's not the span of the bridge that's the problem. And if push comes to shove, it isn't even the super heavily overbuilt depth of the structure, or even the height-wasteful use of ballasted track (putting top of rail 780mm above the top of the girders) -- it's that the top of rail is too low (and that the rails are deliberately aligned horizontally to permanently preclude quadruple-tracking) because Caltrain's rent-seeking self-serving consultants and staffers have no aim at all beside maximizing project budget and minimizing public benefit. This is a local streets project to be undertaken at a quite literally unbelievable cost of by an out-on-control mafia organization.

      Keep the same seven horrible traffic lanes. Keep the same 2.5m crazy-deep bridge structure, even. But elevate the bridge over the road, and shift the tracks about 9 feet eastward to make space for future (flanking FSSF) express tracks.

      As a comparison, the San Bruno Avenue and San Mateo Avenue bridges in San Mateo both have pairs of 62 foot 18.9m spans and 1.692m deep structure (= 721mm on top of 3.17 foot deep "W36x361" steel beams. The single 84 foot 25.6m Angus Avenue span is deeper at 1.96m, but still a full half metre (1.64 feet) shallower than the Broadway Burlingame set-dumpsters-of-cash-on-fire oops-our-bridge-is-too-low gotta-do-all-that-road-excavation scam.

    3. "Are there any scientific/engineering reasons specific to North America or Caltrain as there are roadway bridges with vertical curves right in the middle of the bridge span and passenger rail station with vertical curve right in the middle of the platforms in other parts of the world?"

      No, of course not. Nothing could ever be built anywhere under such strictures ... and by a crazy coincidence nothing (of any use) is exactly what Caltrain has built, at the cost of several billion dollars, over the last three decades.

      But anyway, both of Caltrain's recent grade separation disasters (San Bruno and Hillsdale) feature vertical curves over bridges.
      In the case of San Bruno the bridge over Angus Avenue south of the station is on a vertical curve so comically large that it actually exceeds the 30000m maximum that other countries guidelines max out at even for highest speed lines.
      Clearly this is because a Special Exception from the Caltrain Design Standards was negotiated with Great Seriousness and required the Utmost Mitigation.

      Speaking of vertical curves in platforms -- which you correctly note simply aren't any sort of issue -- the vertical curve at the north end of San Bruno station overlaps the platform by 42.7 feet, rather than being 100 feet distant from it. You can imagine the Extreme Exception Certification Process (and the hundreds of billable consultant hours) this must have required, amounting as it does to a change in tracks and platform elevation of 4.51mm (0.0147 feet)

      In the case of Hillsdale clusterfuck the bridge over 25th Avenue has exactly the gargantum radius (23774m) "required" by Caltrain's freshly ass-extracted design standard for 60mph AREMA freight.

      I can't even imagine "any scientific/engineering reasons" for this self-imposed stricture, aside form the usual rent-seeking and budget-exploding. For an actual *roller coaster* the negative g's pulled on the rails going over a crest exert a force on the structure, but that's simply not the case for gargantuan obese American trains on massively overengineered (literally engineered for unbalanced recipricating steam engine impact loads!) American railroad bridges. And crests are the only cases we happen to care about anywhere on Caltrain. (For sags a tiny argument could be made that the minute additional loading from vertical acceleration affects structure design, but in reality we're talking 0.0031g, ie a 0.3% change in load for civil structures which are overdesigned with safety factors of hundreds of percent.)

    4. Just a quick obvious note re vertical curves on bridges: a vertical curve good for 45mph AREMA freight (110mph AREMA passenger, 182kmh UIC rail traffic, 13270.23 gargantuan metre radius, and what Clem proposes here as a reasonable and uncontroversial and not-even-value-engineered value) rises 21.7mm over the 24m spans we're talking about. So we're talking at most a 11mm change in rail elevation (mid-span) from a flat bridge. Talk about angels on the head of a pin. Talk about pinheads!

    5. As always, thank you so much for detailed explanation, Richard.

      One thing really interesting for the Broadway project is that it seems like the preliminary design was done by the consultants but for the City of Burlingame based on the way the project study report (PSR) for the project was prepared.

      Looking at the project document, I suspect that in addition to consultant(s) trying to make more money out of this whole project, someone at the City of Burlingame had some intentions or gotten a direction from someone else to sandbag Alternative F (the one which doesn't require lowering of Broadway) just to eliminate it. There are a few things which don't make sense based on what you told me about the engineering and actual as-build Caltrain grade separations:

      a) Avoiding vertical curves being on the bridge structure or platform pushed the northern touchdown further north so that it affects not only CP Trousdale but BART tracks(!);

      b) The consultant didn't even entertain alternative phasing: building this using only one shoofly (build grade separation for one track first and work on the second track after the first one is done), which I believe is a common railroad grade separation construction practice outside of North America;

      c) The grade for the southern slope for Alternative F is only at 0.75% (on page 76 of the PSR), and trigger extra impacts to pedesrial crossing at Morrell Avenue;

      d) The cost estimate for Alternative F increased ridiculously from "$180M to $240M" in the initial study phase (on Page 38) to $495 million in the PSR (on Page 35). Even better: utility relocation cost estimate for Alternative A (the hybrid/split-grade design they are pushing) was more than $3 million less than those for Alternative F ($7.8 million vs. $11.6 million). It looks like this is because of the difference in linear feet of telecom/fiber cable relocation, but why does the hybrid option requires only about 500 feet of cable relocation (Page 83 of PSR) while the full elevation requires 13,000+ feet of cable relocation (Page 91 of PSR) when they are literary building the same thing at almost the same location?

    6. I think many station platforms around the world, especially subway systems in Asia, have vertical curves built into them as new tunnels snake around other tunnels and building foundations.

      Talking about self-imposed strictures, can anyone explain to me why Caltrain only allows ballasted track and outright prohibits the use of direct fixation in their engineering standards? I know ballasted track is cheaper upfront, but to ban the use of direct fixation just seems asinine.

      In terms of Broadway grade separation, with the current estimated price tag, you would expect the entire city of Burlingame (which includes the streets near Burlingame station) to be grade separated and quad-tracked.

    7. I think the interfaces between ballasted and direct fixation track sections (where the compliance of the structure has a discontinuity) can be troublesome to maintain. Although I'm tempted to joke that somebody would surely try to tamp the direct fixation section.

    8. Thanks for the extra info Clem. I do see how it can be expensive to maintain. BART has both ballasted track and slab track, and lets face it, they don't have the best in terms of maintenance and ride quality.

      On another note, what is your opinion on Millbrae trying to pressure HSR to go below grade? BART transferred some lots over to the city for development. Undergrounding HSR would be extremely expensive. I doubt Millbrae will get there way, but if they did, I would prefer to tunnel all the way past San Mateo as grade separating downtown San Mateo would be a nightmare. Leave local trains at grade and have express/HSR underground since ROW is so constrained there. But hey, tunneling through Millbrae to San Mateo would probably cost an extra $1 billion.

  12. "grade separating downtown San Mateo would be a nightmare"

    Not really. The only problem is that there really isn't space for temporary "shoo-fly" diversion tracks through the narrowest part of San Mateo, so severing the line -- for months, not years, if undertaken by adults -- while foundations and bridge support columns are placed in the ROW and precast bridge sections are erected over them is the "pain". Much of the way, say south of Fifth Avenue, there's space to do all the advance work without much affecting service.

    Plan ahead, do things right, get a single through track back in service in a few months, and then, over a year or so, get the station built and the other three or four tracks in place and in service.

    Doing Burlingame is easy, literally insane local government aside.
    (And Caltrain engineering consultant professionalism and ethics aside.)

    PS If you were really going whole-hog with the tunnel mania, El Camino Real is both more direct and flatter than the Caltrain line. But you don't. You really really don't.


  13. Are there any solutions or ways to deal with "literally insane local government"?

    Looking how things folds in the Bay Area transportation projects, local governments are insane. They block or kill the solutions which are obviously the best from the technical standpoint by weaponize studies after studies, "public inputs", and "voice of constituents", and probably contributing a lot to the crazy cost increase while making feasible project infeasible.

  14. I don't think local government is the problem when compared to NIMBYS. They are the ones that try to stonewall any project that benefits the greater good. If grade separating San Mateo means putting the tracks on a viaduct, people are going to flip their shit. This is in spite of the fact that downtown San Mateo has several auto bridges that carry cars from one parking lot to another. Quite frankly, viaducts can be made to look beautiful, it doesn't have to be grey. You can have decorative arches or use the space underneath to have stores and offices. London, France, Tokyo, and etc have ancient arched brick viaducts where they retrofit the arches to have stores, bars, and restaurants. Viaducts can easily be made to fit architecturally within their environments.

  15. In case you haven't seen the latest Caltrain news:

    The launch of electrified service on Caltrain has been delayed by two years until late 2024, and the cost of the project has risen by $333 million to $2.3 billion, the transit agency announced Thursday.


  16. Well, it's not like we didn't see this coming. The mismanagement from Balfour Beatty and Caltrain has been diabolical. Slow foundation production, unmarked debris and artifacts while potholing, slow pole erection, and to top it all off, the whole mess with constant wait time crossings being converted to dual speed check. What a shame.

  17. It gets worse:

    Contracting options
    - Plan A: Global resolution with Balfour Beatty
    - Plan B: Descope all signal system work from Balfour Beatty; contract directly with third-party contractor


    1. This is by far the biggest "OOOF" moment I have ever seen. How did it get this far? We have known for ages that AC electrification requires signals to be converted from DC to AC. We are already more than half way through construction and they are NOW contemplating on whether or not BBY should be doing the signaling even though they were contractually obligated to. I smell a lawsuit coming similar to CBOSS. This has been going on for quite a while now but they are finally making it public. The funny thing about dual speed check is that it's supposed to be temporary system until they have "Wireless gate signaling". So are they telling us that they paid BBY all that money for them to implement a signaling system that will be made redundant later on?? WHATT?? This is disgusting mismanagement and complete lack of foresight. Maybe Siemens or Hitachi can step up to fix the mess that BBY and Caltrain is making.

  18. So a quick summary of Clem's points:

    * Utility relocation: Caltrain and Caltrain's perma-temp consultants will and can and do and are outright lie to elimiminate "alternatives" that do not involve extensive local roadworks, extensive local street excavation, and huge amounts of utility work. We know this for a fact from the Hillsdale grade separation disaster and we are seeing this as a fact in their catastrophic Broadway Burlingame plans.

    Again: the facts are unambiguous: Caltrain's perma-temp consultants and Caltrain's "public" staff are simply outright lying when they claim that low-utility low-roadwork alternatives are infeasible.

    * Vertical curves made for freight trains: Caltrain and Caltrain's perma-temp consultants will and can do anything to explode the cost of grade separations. The fact is that the freight speed limit everywhere on the Peninsula is 50mph and the facts are that recent Caltrain projects in San Bruno, downtown San Mateo and Hillsdale all feature AREMA 50mph freight (not 60mph) vertical curves, and it unarguable that freight should be entirely kicked off the line, not pandered to, and certainly not drive hundreds of millions of wasted public expenditure. Designing vertical curves to pander to even AREMA 45mph freight (recall 13270m radius, good for 180kmh passenger and freight in the civilized world) isn't sane, but at least it isn't insane. Caltrain's freshly ass-extracted 60mph "requirement" can only be seen a pure, unadulterated rent-seeking by engineering consultant and construction scum. There is no possible justification, and there is no chance that 50+mph freight can run anywhere else on the line. There is zero possible explanation aside from fraud.

    * Vertical curves that can't overlap bridge spans. Once again, not only is there zero engineering reason for this ass-extracted angels-on-the-head-of-a-pin "requirement", but Caltrain's own San Bruno and Hillsdale grade separations feature vertical curves continuing through road overbridges. They're not even trying to lie believably: this is all just a big "fuck you we can get away with saying anything and doing anything just watch us. Also we demand more funding."

    * Paint-by-Numbers Structure Depth. Caltrain's structure depths are only getting "deeper" with time. Oh no! We need to excavate several acres of roads because oh how oh how could be ev very get under this big bad old choo choo concrete wankfest? Oh please don't make us excavate all those roads! Don't make us siphon creeks! Oh no,.

    * You unexpectedly didn't explicitly call out Vertical grade limits made for freight trains but you should have. Caltrain and Caltrain's perma-temp consultants seem to love imposing an absolute limit of 1% at the time of alternatives "analysis" in order to kill off anything reasonable or cost-effective. Note that a 1% limit is what you'd expect on a heavy haul diesel coal line. It's completely unreasonable in the Caltrain suburban environment and Caltrain operating environment, where 1.5% or 2% grades ought to be routine.
    Oh, and Caltrain's San Bruno grade separation is 1.25% on the north end climbing from under Highway 380. So much for requirements. But hey, strangling cheaper alternatives in the crib is the name of the consultant budget-busting game, and these people sure play the game.

    (PS Hey, anybody seen that $300 million of public money that Caltrain's exact same staff and Caltrain's exact same perma-temp consultants were directly responsible for incinerating on CBOSS? Anybody? Hellooooooo... )

    1. I have heard engineers say "Well, this isn't the final design, we're trying to estimate worst-case scenario impacts; things will get tightened up as we get closer to 100% design"

      In my very small-n observation, this approach is maybe common in design-build contracting. Very rudimentary preliminary engineering before handing it over to the design-build contractors, who then bid based on that plan. The winner inherits a design with *plenty* of room to "trim the fat" thereby adding to their margins (but not reducing the cost to the public *at all*)

    2. Owen, I don't think you understand the extent to which "Alternatives Analysis" and "Project Study Reports" and "design guidelines" are actively weaponized by consultants and staff to pre-determine the very worst and very most expensive outcomes.

      These aren't innocent mistakes by inexperienced underpaid rubes. This isn't "defensive design". This isn't "unforeseen changed circumstances".

      It's outright self-serving rent-seeking vendor-captured fraud actively abetted and encouraged by "public" sector corruption.

      All it takes to see that the secret-until-it's-years-too-late Burlingame Public Study Report is deliberately and laughably fraudulent are about a half-dozen approximate survey numbers (rough x/y coordinates of project limits, grades at limits), a half-dozen geometric parameters (and these are to a very large extent freely chosen potentially-self-sabotaging parameters: maximum grade, vertical curve radius, platform length, maximum platform grade, minimum road-to-rail clearance, etc) and some primary school second grade level linear algebra (multiply, add, subtract, really, that's it.)

      It's the same every single time. The Transbay Terminal. BART to anywhere. Every Caltrain grade separation project. Every Caltrain station plan. Every Caltrain "modernisation". The fix is in and every remotely rational or remotely cost-effective notion has been drowned in the bathtub long before you even heard that they were even considering having already spent a few million on "preliminary studies" by "on-call" consultants and "in house experts".