What follows is an analysis of the far-reaching cost and schedule implications of Special Provision SP01040.
Special Provision SP01040 imposes the following time restrictions:
- No work during weekday peak hours (6 - 10 AM and 4 - 8 PM)
- No work on Tuesdays and Wednesdays overnight, for track maintenance
- Only one track available mid-day, evenings and weekends
- Two tracks will only be available in the early morning hours Friday - Tuesday.
If you want to analyze a typical work week on an hour-by-hour basis, you can define six different track availability states. Each state has associated to it an availability factor, which you can think of as how many tracks are available to perform productive work (i.e. re-signaling or constructing the overhead contact system).
|Availability State||Availability Factor|
|Mob/Demob for 1 track||0|
|Mob/Demob for 2 tracks||0|
|Single track available for work||0.75|
|Mob/Demob for 2 tracks with 1 track already available||1|
|Both tracks available for work||2|
The corridor has been divided into geographical segments, at least some of which must remain open at all times to allow northbound and southbound trains to meet and run past each other. Each segment has a certain length (measured in route-miles).
|Segment #1, MP 0.3 - 8.0 (CP 4th to CP Sierra)||7.7|
|Segment #2, MP 8.0 - 29.1 (CP Sierra to CP Alma)||21.1|
|Segment #3, MP 29.1 - 44.5 (CP Alma to CP De La Cruz)||14.8|
|Segment #4a, MP 44.5 - 47.5 (CP De La Cruz - CP Alameda)||3.0|
|Segment #4b, MP 47.5 - 51.1 (CP Alameda - Tamien)||3.6|
|Yard Facilities (4th & King, CEMOF, San Jose)||3.0|
During the first phase of electrification, work may only occur in segments 2 and 4, with both tracks open in segments 1 and 3 to allow trains to meet. Then, following an adjustment to the timetable, the second phase of the work will occur in segments 1 and 3, with both tracks open in segments 2 and 4 to allow trains to meet. This allows Caltrain to maintain hourly service in both directions during mid-day, evening and weekend periods, single-tracking as needed around electrification work sites.
Let us loosely define a unit of labor to perform electrification work on one mile of track for one hour (however many people that may actually take). One labor unit is multiplied by the number of track miles and the number of hours to calculate a burn rate, or how much the labor will cost during any given period of time, assuming the contractor makes full use of the work windows.
We will assume that when both tracks are open, efficiencies can be realized so that only 1.5 labor units (rather than 2) are required to work on 1 route-mile (2 track-miles). We can then assign a labor cost for each track availability state defined above:
|Availability State||Hourly Labor Rate|
(per route mile)
|Mob/Demob for 1 track||1|
|Mob/Demob for 2 tracks||1.5|
|Single track available for work||1|
|Mob/Demob for 2 tracks with 1 track already available||1.5|
|Both tracks available for work||1.5|
|Day of Week||Overtime Factor|
|Monday - Friday||1|
Now let's pull all these assumptions together and come up with three metrics.
- The first metric is average track avaibility, measured in track-miles. It measures how much of the railroad is available for actual productive electrification work, as opposed to shuffling workers and equipment or dodging out of the way of trains. Average track availability is inversely proportional to how long it will take to complete the work. If you double the amount of available track, the job can be done in half the number of weeks. There are limits to this assumption, of course, but for sequential tasks requiring direct access to track, such as re-signaling and constructing the overhead contact system, this inverse relationship is quite reasonable.
The way to compute average track availability is to assign each hour of the week a track availability state, based on the rules set out in SP01040. Then, we multiply the availability factor (associated to that state) by the number of route-miles in that segment to calculate how many track-miles are available for work in that particular hour in that particular segment. We can repeat this calculation for every hour of the week (24 x 7 = 168 hours) and for every segment. Finally, we can add it all up and divide by the total number of hours in a week to figure how many miles of track are available on average.
But it's not quite that simple. Since the work is divided into two geographical phases, we must first add up the availability for segments 2 and 4 (Phase 1) and then separately add up the availability for segments 1 and 3 and the yards (Phase 2). The average track availability for Phase 1 and Phase 2 is then averaged; this average is weighted by segment lengths to serve as a proxy for duration of each phase.
- The second metric is burn rate, measured in labor units per week. It measures the rate at which money is spent on all the work, including not just actual productive electrification work but also the shuffling of workers and equipment and the dodging out of the way of trains. This metric assumes that the contractor makes full use of the available windows, and that no additional hourly expenses are incurred outside of the work windows (e.g. due to the work not filling a full 8-hour union shift).
The way to compute burn rate is to multiply the hourly labor rate (associated to each hour's track availability state) by the number of route-miles in that segment and the overtime factor for that particular day of the week, to calculate how many labor units are expended in that particular hour in that particular segment. Once again, we need to be careful how we add up the labor for Phases 1 and 2, using the same partial sums and weighted averages as for track availability.
- The third metric is installation efficiency, measured in labor units per week per available track mile. It measures how much of the labor is expended on actual productive electrification work, as opposed to unproductive tasks such as the shuffling of workers and equipment and the dodging out of the way of trains. It serves a rough measure of the overall cost of tasks requiring access to the track, such as building the overhead contact system and re-signaling. It is defined simply as burn rate divided by average track availability. A lower number is better, indicating that a given length of track can be completed using less labor.
Armed with these metrics, we can analyze and compare a variety of electrification scenarios, including the baseline scenario specified in the RFP per Special Provision SP01040, and other scenarios of our choosing.
For the detailed calculations that support each scenario, or to explore your own scenarios and change any of the assumptions, you can download this Excel spreadsheet.
- Baseline Scenario: Let us scrupulously apply the work window restrictions from Caltrain's RFP, per SP01040. Phase 1 has an average track availability of 13.3 track miles, while Phase 2 comes out to 12.1 track miles. The weighted average of the two phases yields an average track availability of 12.7 track miles. Bearing in mind that Caltrain has over 100 track miles to be electrified, this works out to a paltry ~12% of the railroad being available, a reflection of the extremely restrictive work windows. This does not bode well for the program schedule, since having so little of the railroad available to the contractor will draw out the duration of all activities requiring access to the tracks.
The burn rate works out to 3934 labor units per week, much of which is spent on mobilization and demobilization, as well as on weekend overtime work.
The installation efficiency is 309 labor units per week per track mile. When you consider that there are only 168 hours in a week, that is a terrible score indeed.
- Weekend Shutdown Scenario: One way to improve the average track availability is to completely shut down the railroad on weekends. While this concentrates the majority of labor onto weekends when overtime rates are high, it opens up a 54-hour long period of uninterrupted access to segments 1 through 4a, while segment 4b and the yards remain partially open (to support tenant railroads and Caltrain maintenance activities). This allows weekend work to be performed simultaneously in all segments, during both Phase 1 and Phase 2.
Not surprisingly, average track availability improves considerably, with 35.3 track miles for Phase 1, 35.6 track miles for Phase 2, and a weighted average of 35.4 track miles. By shutting down the railroad on weekends, we effectively tripled the amount of track access afforded to the contractor.
The burn rate goes up quite a bit, because the entire railroad is being worked on every weekend. The total works out to 8044 labor units per week.
The installation efficiency is 227 labor units per week per track mile, a savings of 27%.
- Friday + Weekend Shutdown Scenario: The next possible step is to shut down the railroad on Fridays to extend the weekend work window to three days. This has the advantage of increasing availability during a non-overtime weekday, but it is disruptive to riders who need to commute five days a week. Weekend access increases from 54 hours to 78 hours, again with all four segments being worked simultaneously.
Average track availability increases to 45.4 track miles. Burn rate increases to 9144 labor units per week. Installation efficiency improves to 201 labor units per week per track mile, a savings of 35%.
- Total Shutdown Scenario: The most draconian possibility is to shut down the railroad entirely. It would be extremely disruptive for riders. It could very well gridlock the highway 101 corridor, and in so doing, drive home the value of Caltrain for hundreds of thousands of commuters who never use Caltrain. It would leave freight customers high and dry. On the plus side, it would enable a coordinated construction "blitz" to complete the work at lower cost and far faster. Electrification could even be combined with other projects such as grade separations. Segment 4b and the yards would remain partially open (single-tracked) for the tenant railroads that use the southern end of the corridor.
Average track availability would shoot up to 98.2 track miles. Burn rate increases to 15600 labor units per week. Installation efficiency improves to just 159 labor units per week per track mile, a savings of 49% (half off!)
You might wonder about the point of this exercise. The RFP is closed and all the bids are in, so isn't all this overcome by events?
Word has it that the bids came in much higher than Caltrain expected, with contractors blaming the restrictive work windows for the higher cost. Caltrain is now scrambling to scrape together even more funding than the $958M they thought electrification would cost (not including new vehicles). Recall about half of that sum was estimated for re-signaling and building the overhead contact system, tasks where cost and schedule are strongly driven by work windows.
Shut Down This Railroad!
The right answer isn't to go digging between couch cushions for another several hundred million dollars. The right answer is to shut down this railroad, because trying to electrify without shutting it down is like trying to change a flat tire without stopping your car. A weekend shutdown would speed the work by a factor of nearly three, and reduce cost by about $150 million. Shut down three days, save $200 million. Shut everything down, save nearly $300 million. Okay, maybe don't shut everything down, but at the very least, the weekends must go.
This will make for a really terrible year or two of construction (Guessing, no idea how long it will actually take!), but I think you might have a good point. More likely and palatable than a full three-day shutdown would be, I think, shutting down Friday evening, right after rush hour, and then opening up just before rush hour on Monday. If we say an average of 7:30pm on Friday, by canceling all of the evening locals, and then canceling the morning locals on Monday, opening again at about 6am, that gives a 58.5 hour Window, minus mob/demob.ReplyDelete
One thing I would be concerned about is that having everything shut down for a time might damage long-term ridership. I know Caltrain is in high demand, so it would probably recover promptly, but it's still something I'd be concerned about. People who bought cars because they needed to commute during the shutdown, and then decided not to sell them afterwards, because having a car is still pretty convenient, that sort of thing.
Would there be shuttle bus replacement service? If so, how much would that eat into the savings?ReplyDelete
For weekend shutdown: What happens on big event days, like Giants games? Halt work and run a special schedule? Perhaps if Caltrain were clever, they would ask organizations like the Giants to contribute towards the cost of halting work if they want fans to be able to arrive those days by train.
I didn't go into special event restrictions, which are spelled out in SP01040 paragraph 1.05. There are more than 100 yearly interruptions for special events. You can guess what that will do to average track availability and installation efficiency: it only gets worse.Delete
Shutting down does not mean that the whole line has to be shut down, because of the limited number of "skilled workers". Assumed we have the suggested Friday evening to Monday morning window, only one segment can be shut down at a time. That also means that the shut down segment can relatively easily be bridged with replacement buses. However, if a segment can be closed completely, this would give the opportunity to do more work than just signalling and electrification, but also trackwork etc. (which is, in my understanding, not part of RFQ).ReplyDelete
And about "skilled workers": Where in the US do you find skilled workers to do mainline electrification? The ones working for the last major project have probably all retired by now, or are no longer skilled. I wonder how much could be saved by "importing" expert teams (such as from F&F or K&M, maybe even with their own equipment). These guys do that for a living, and know what they are doing. And they don't need to interrupt work for 8 minutes when a train passes on the other track.
I doubt that skilled workers will be hard to find for the actual hands-on installation work (as opposed to engineering). The skills involved are not unlike those needed to build and maintain our electric grid.Delete
We may have a different perception on this issue…Delete
How was it when Amtrak electrified New Haven to Boston?
"The skills involved are not unlike those needed to build and maintain our electric grid."ReplyDelete
Only for the parts of the work that are away from the track and don't require track time, flagging, etc.
Sure there are Americans who can install HV transformers and run supply lines to switchyards.
But installing railway catenary is indeed a skilled profession, one whose efficiency and throughput improves with experience.
It's not about switchgear. It's about medium-high repeated installation and positioning of lineside civil structures (foundations, masts). It's about familiarity with the overhead hardware (hangers, insulators, clips, cables) and knowing what and what doesn't work to get it snapped in place rapidly, repeatedly, and reliably. And totally unlike HV transmission lines, there's a ton of skill involved in stringing and tensioning the contact and catenary wires, the droppers that connect them, the hardware that clips them to the hangers, the hardware that anchors and tensions them, etc, etc.
If Caltrain gave a fuck about throughput, cost, cost-effectiveness, this would all have been done as a turn-key system, with skilled and experienced companies (the absolute diametric opposite of Caltrains' rent-seeking basket case consultants!) proposing packages of design (their own, known-quality overhead systems, not Caltrain's home-brew bullshit; their own tested design rules for pole placement and spacing, not Caltrain's bullshit made-up over-cost, intrusive, unique "standard"), build with their own high-throughput installation trains and skilled installation teams (not Caltrain's special needs make-work welfare program and made-up work rules and made-up safety requirements and made-up work windows), with guarantees of continuous quality control, and with active contractual incentives for work rate.
And don't let's get started on a completely new signalling system being secretly bundled into the "electrification" after we've already been actively and unambiguously and in-your-face defrauded of $250 million on CBOSS.
Remember, we're talking 50 route miles for all of this. The costs, the one-off-manship, the consultant overheads, the low productivity, the worksite overheads, the schedule slippages, the scope creep, are all off the scales for such a tiny, isolated, simple, nearly-zero-traffic turn-key shuttle line.
Does your cost analysis take into account, the operating losses CalTrain will incur by have to reduce or stop service?ReplyDelete
Caltrain operates at a loss. The less it operates (especially on weekends when trains aren't full) the less is lost.Delete
Given how incredibly slow Caltrain's weekend service is, replacing it with shuttle buses won't actually make things that much worse on many sections of the route. I suspect that you can also get away with partial closures on weekends, closing only half (or a quarter) of the line and running trains only on the other half. Closing the northern half in particular wouldn't be terrible: the SF to Millbrae section has BART as a pretty functional alternative for everything but the baseball trains, and the stops between Redwood City and Millbrae are so closely spaced and service so slow that even an all-local bus service would hardly be slower. As an added bonus, any bus service that connects to Millbrae can run on BART headways, which might end up offering better service than weekend Caltrains, since frequency would be tripled, even if trip time ends up somewhat slower.ReplyDelete
They did a bus bridge on weekends for the San Mateo bridges replacement, they can surely do the same for electrification.ReplyDelete
Clem it might be worth looking over the whitepaper from the CTX project and how lessons can be applied here:ReplyDelete
The original Baby Bullet CTX project where passing tracks were added along with new signals and rebuilding of much of the rail.
Caltrain was shutdown over the weekend and bus bridge serviced the following stations:
* San Jose Diridon
* Palo Alto
* SF 4th & King
Looking at old documents, this required 25 buses and cost $6 million back in 2004. For baseball service, they needed 30 additional buses for that event. I recall that the runtime was about 2 hours in each direction.
Today, I'm guessing that bus costs will be higher due to higher ridership, increased traffic and inflation as these are costs from 10+ years ago. Also, that assumes you visit the same stations, but ridership could change. Still, worth factoring that in.
Also, there are similarities for electrification to the CTX project in that it impacts all service, there are also major differences. For CTX, track was physically ripped up and replaced. Grading and bridges were rebuilt. Each "blitz" had to put track back together into a workable state. You can't just leave rails unconnected when done. With electrification, you're not affecting existing infrastructure, so you can leave a mast foundation unfinished or catenary not fully calibrated.
Here's a PDF with all the info from CTX that I could find:
Thanks for that refresher on the CTX projects. Too bad that so much of that signal and crossing circuitry will have to be torn out and replaced so soon to be made compatible with a 25 kV electrified system. After Ponderosa, CTX, CBOSS and PCEP, we'll be looking at over half a billion dollars spent on signaling, overlaying, re-signaling and re-underlaying 50 route miles of track over 2 decades. Why do it right when you can do it twice?Delete
.. does that make 3 iterations of signalling? :)
Another option to consider would be long-term single tracking. So long that it would be worth changing the schedule over. That would save time of mobilization and demobilization, and the track used can be switched halfway through.ReplyDelete
That would destroy rush hour capacity, Caltrain's raison d'être and its bread & butter... I think long-term single-tracking would be worse than a total shutdown.Delete
Is there considerable trackwork planned within the scope of that RFQ?Delete
If not, there is not really a need of anything long-term, because a lot of time is spent waiting for concrete to set… something which concrete does even if there are trains passing very nearby… So, weekend closures would probably be the most efficient approach.
No track work, though I would not be surprised if South San Francisco station reconfiguration ends up overlapping poles-and-wires-and-transformers. (Or, worse, and likely, in typical Caltrain out-of-control throw-random-stuff-together style, bundled into the "electrification" contract.)Delete
(Advance pre-electrification rationalization (ie removal) of useless track would make sense, but instead Caltrain plans to electrify all the useless bits. Lipstick on a pig at every turn.)
However total re-re-re-resignalling to 19th century standards is included in their portmanteau over-bulging contract, with track circuits (US Special Local Conditions to not permit axle counters, nor ETCS, nor ...), and existing bad block lengths and locations, and insulated joints, and massive lineside signals, etc, all mandated. And everything anywhere on the ROW needs to be grounded, and running rails electrically bonded to return, etc. which is all going to take real track time beyond near-track business like foundation excavation, foundation pouring, stanchion erection, hanger hanging, etc.
"Design build". Right. Right ...
I just don't see how Caltrain can maintain any reasonable capacity with single tracking. Also, the location of crossovers isn't conducive to single tracking efficiently.Delete
The crux here is that you need to provide replacement service for people who don't have cars or other options than Caltrain for commute. Buses could work but if weekend service required 25 buses, I can't imagine how many you'd need for weekdays.
I hate to sound naive, but the idea of a weekend shutdown sounds so common-sense that I can't see any other way Caltrain would/could plan any track work. Even given the complicated metrics behind it, weekend shutdowns still come out as the best possible option.ReplyDelete
This is not rocket science. Even NZ Government Railways had it figured out on the Wellington electrification projects, and electrification maintenance, decades ago.ReplyDelete
Close only *part* of the line, both directions, on weekends. Say a fare segment, or even less. Run bus shuttles between the affected stations. Do the electrification work is done in segments of a-small-numbers-of-contiguouos stations.
Yes, there is schedule impact, but it's better for riders than a complete shutdown.
On a related construction note, I was looking at the progress of San Mateo Bridges project. I'm actually impressed how little resistance was put up by the city when building the retaining wall and clearing vegetation. This also clears the RoW for potentially adding extra tracks more easily.ReplyDelete
However, has anyone noticed that the retaining wall is rather low? It works fine because the ballast slopes up to meet the raised tracks, however, how would you put an extra track in that space? Let's ignore the width for now, but if you put a new track, wouldn't you also need to raise the retaining wall - which doesn't look easy. Alternatively, you'd need some kind of structure for the additional track, but it wouldn't be as simple as just adding ballast and laying track.
Does anyone know more details of this project?
Your observations are correct.Delete
The San Bruno bridge and berm reconstruction was deliberately not designed for widening to three tracks even through it would have been almost trivial (design, impact, even cost) to have done so.
Your observations about the (non) response to the dreaded NIMBYism is also accurate. As we have seen time and time and time again with PBQD/Bechtel pulling the strings at their 100% owned subsidiaries BART, MTC and CHSRA, "NIMBYs" and "concerned local government officials" can and are manufactured at will, and their important local community insights and contributions and concerns and are invaluable and valued only when they improve the profits of the limitlessly corrupt transit-industrial mafiosi. Otherwise, they're brushed aside and the cash rolls in, always to the worst (cost and design) project "alternative".
So yes, Caltrain once again chose to do the wrong thing, because that's what they always do, because what's the downside? Termination? Defunding? Ha ha hah!
America's Finest Transportation Planning Professionals: death is too kind a fate.
All this talk of pantograph installation has made me fondly remember one of my favorite youtube videos; Pantograph Damage!!!!! Best experienced while listening to Enya: https://www.youtube.com/watch?v=XgCPPeYmyKwReplyDelete
Question for Clem,ReplyDelete
As you're probably aware the Next Generation Equipment Committee chose Nippon-Shayro as their bilevel equipment manufacturer going forward. My question is, are the bilevels they are going to make are lower-level gangway galley cars (ala Caltrain), or upper-level gangway cars (ala Amtrak California).
I ask because in all their official *proposed* "concepts" they wanted the latter, but nowhere I can find where it's actually codified and I can't find any pictures of the prototype cars N-S apparently built (the production cars will apparently be delivered later this year). It doesn't really apply to Caltrain or CAHSR *itself* since they are going with EMUs, though.
Does this mean the end of galley cars or lower-level gangway bilevels? The more I think about it, the bigger the problem this could be since upper-gangway bilevels obviously can't work with single deck cars. It also means no compatibility with Bombardier's bilevels either.
Upper level gangways. Compatibility with gallery cars or Bombardier bilevels was never a requirement, but compatibility with California Cars was (if I recall correctly). No problem if you ask me, since these cars have no place in a "blended" system here on the peninsula.Delete
Changing a tire while driving is totally possible:ReplyDelete
At some point, if you're going to buy new rolling stock anyway, you may as well just make battery-pack locomotives and have robotic quick-change stations at the end of each line. I'd estimate around $500K/pack at current consumer rates for a 3MWhr pack. Reserve $300m for fast change & charging infrastructure at the ends. I don't know how many trains are on the rails at any given time ... even if there are 20, and you wanted 4 total packs each (running, charging, 2x backup), that's only $40m in batteries.
A battery+inverter car could be added and permanently Siamese'd onto existing locomotives to make them forwards compatible. By the time the diesel block and fuel tanks were removed, you probably wouldn't even be adding any weight.
All the construction happens at the ends of the line, the entire system can run in-place full time meanwhile.
Or just buy a TBM and extend underground BART the whole way down...
The point of electrification is to introduce electric multiple units, which accelerate more rapidly than locomotive-hauled trains, allowing shorter journey times and higher frequencies even if the maximum speed is the same. An EMUs also carries more passenger than a locomotive-hauled train with the same overall length, because every vehicle in the train is carrying passengers.Delete
Ahem. Some of us distinguish between "EMUs" and "trainsets".Delete
EMUs have the benefit that (ignoring platform-length constraints) you can couple on one more unit, and have the same power-to-weight ratio, acceleration, and braking curve. So there's no schedule penalty for growing a given scheduled train by an EMU or two.
Crewing issues are a whole different matter. So are antedeluvian FRA regulations, which require a retest of the 19th-century pneumatic brakes under such circumstances. ("It's another locomotive!")
which reminds me... when I read about Caltrain getting more-or-less off-the-shelf UIC-compliant EMUs, a nai"ve person (like me) might think the EMUs will come with Scharfenberg couplers, or other automatic couplers which connect all the necessary cables, pneumatics, whatever, between the coupled EMUS, all in one fell swoop, and not requiring manual inspection by another employee. In hindsight, that's probably _very_ naive.
Clem, what's your take on that?
apullin: numbers matter.Delete
Look at some decade-old EMU technology, the Swiss RABe 514.
Max speed is only 140 km/hr, or 87 mph; a lot slower than CAHSR is expected to run on the Peninsula.
But worse, their power output is rated at 3.2MW/hr. Are they going to make it from one end of the line to the other with a 3MW-hr battery? Only if they accelerate slowly, one suspects. And their peak acceleration is 1.1m/s. Yeah, let's have locos lugging around tens of tons of batteries, and end-to-end run times close to the current diesels.
Clem, can you plug in some numbers from your EMU-of-choice? You have the spreadsheets.
And one last fun fact for your "Siamese twinning" idea: if you remove the diesel engine and generators from an F40PH, the FRA is going to make you fill it with concrete ballast to match the original weight. Yes, really.
Vicious rumor spread by disgruntled fanboys. It was designed to have that much weight in it and when it's taken out it handles poorly. In non third world countries if they couldn't change the regulations they would have bought something more appropriate instead of hacking it into a cabbage car.Delete
Re your question about couplers, please see the EMU RFP, Vol 1, Section 5.
Basically, proposers are allowed to propose different types of coupling mechanisms, they're not limited to a certain type.
@kiwi.jonathan , The number sure do matter, although I only picked up a little bit of data from here and there. After a little more looking, it seems like a 3MW diesel genset is around 22Mg. Using the Tesla 85 KWh battery as a reference, 544 kg/85kwh, then a 3MW battery ends up being about the same weight as the engine that you could forgo, around 20Mg. Even then, there's another 1000kg or so of fuel (estimated, I can't find info on tank size) to be removed.Delete
It is also not clear if the powerplant really does output 3MW continuous during operation. The engine & generator are likely sized for maximum power output, and the average would be lower. I'm sure CalTrain has some telemetry on that which could be used to size the battery appropriately. Then, of course, there is significant regeneration to be done during breaking and downhill segments (even though SV is totally flat...). Do the current locomotives have a regeneration system of any sort? I don't see that this plan is disqualified by any numbers.
Moreover, this plan would still be compatible with EMU's, although still with the addition of a battery "car", in which case the battery swap out could likely be done significantly cheaper, by just swapping the whole car itself. The battery car would just provide a power bus to be shared between all the EMU's by serial connections. The same EMU's could be bought and installed, with the addition of an on-board high power bus and electrical connectors at each of the ends of the car.
Assuming linear scaling, a battery of that size would be able to support a power output of 15MW or more, so addition of extra EMU cars would not hit a clipping point in the power/mass ratio, and you still have the advantage of the drive system being distributed and scaling with the number of cars. All that remains to figure out is in this case is the same as above: what actual design capacity is needed to haul a given train length from one end of the track to the other.
This would forgo the entirety of building the overhead power distribution in the field, so no shutdowns, and should cost way less than the CalTrain $1b estimate (although I am still reading how much of that is signaling, grade and bridges, etc apart from the electrical system). Either way you are stuck with acquiring new rolling stock, but with the battery plan, there is a straightforward way to update an existing motive to work on the new system, further lowering the time horizon of getting the electric trains running.
The issues isn't a "clipping point", it's that adding more cars reduces the power-to-mass ratio, which in turn impacts acceleration, and thus trip time.Delete
Add more cars to your battery-powered consist, and that consist runs slower.
All of this talk of battery locomotives strikes me as a (untested) solution in search of a problem. Just electrify the whole system, as that infrastructure is a long term investment (somethings used for decades, even centuries), compared to the stop-gap, short-term politically expedient nature of the battery system. I'ts worth noting that in a place where battery electric trains are in actual revenue service (Japan), the system is 100% emu, with none of this locomotive nonsense, and the trains are short (two cars) used on mainline to branchline service. When you get higher pax loadings than a two car train can handle, might as well electrify, or just stay with diesel if the money isn't there.Delete
See my earlier write up on the hybrid DMU, unicorn of the rails.Delete
BART has(had?) problems this past week between Baypoint and North Concord.ReplyDelete
Some 50 cars were damaged by power surges.
While working on the problem, BART ran a bus-bridge between those stations
The week after the initial problem, BART instituted a shuttle train between BayPoint and North Concord during "commute hours", with a bus-bridge during middle-of-day and after 8pm.
much less impact than total weekend shutdown, or total weekend bus-bridging.