27 July 2010

Odd Stacking

The odd stacked alternatives shown in the figure at right (ripped out of a recent technical working group presentation) make little sense, for a number of reasons that were previously discussed.

Recall that track stacking, besides entailing very intensive and profitable construction of complicated earthquake-resistant civil structures on the taxpayer's dime, is intended to reduce the right-of-way width required to build a four track corridor, presumably to appease neighbors and minimize residential property takes. A brief glance at the above drawing (which should also reinforce fears of a separate-but-equal approach that is disastrous for Caltrain) necessarily leads to ONE of the following two conclusions:
  1. The planners have lost sight of what they were trying to achieve, in effect destroying our village in order to save it. The stacked solution on the left requires "only" 87 feet of ROW width, while the one on the right requires 119 feet of ROW to make room for a Caltrain platform down in the trench. These elephantine structures, making use of enormous amounts of concrete, seem to miss the whole point of stacking: to save space. If you were to nibble back just 4 feet out of the 13 feet (thirteen!) devoted to drainage and third-party utility easements, you could simply stick all four tracks down in that trench on 15-foot centers. Dear peninsula communities: do you prefer 13 feet for drainage and utilities, and oh, by the way, a viaduct that looms 30 feet above ground level (16 feet of road vehicle clearance, 10 feet of viaduct box + rails, and 4 feet of sound wall) with another 30 feet of overhead wires towering above that? Or would you rather we cut back to 9 feet for drainage and utilities, and the viaduct disappears entirely? Let's think it over, for about a microsecond.

  2. The planners are not so subtly trying to sand-bag the stacked options to gain community buy-in for property takes. Making the stacked alternative look this bad on paper fulfills the dual goal of giving it environmental due diligence under CEQA and ensuring that public opinion will be "stacked" against it, setting it up for being "not carried forward" in a way that is impervious to future litigation. These are the lengths to which we must go to take 5 feet of somebody's back yard.
Since one would prefer to assume that planners are not stupid, and that they don't take peninsula residents for idiots, #2 seems more likely. Stay tuned for the answer: the supplementary alternatives analysis report for the peninsula high-speed rail project is scheduled to be revealed to the public on Thursday, August 5th in San Francisco.


  1. political_incorrectness28 July, 2010 01:50

    This is what I am concerned about is that the idiocracy in Bay Area planning will bring the projet down. I was hoping CA4HSR's comments were going to be taken seriously but it seems as if the planners heads are stuck up their asses.

  2. Given the sub-optimal design of the stacked pairs, still I believe discussion is not totally without value. (but I am not a rail systems engineer so what do I know?)

    Would there be any advantage to run the north/south pairs in the same level?


    This would allow for cross-platform transfers and avoid running up/down stairs during an express/local overtake stop.

    I presume freight would run time separated on the slow lower level track.

  3. It appears to me that this stacked option discussion is in fact simply part of the required analysis for CEQA. There is no convincing reason to construct the monster depicted on the right. The point most likely being made is that there is no advantage when it comes to stacking.

  4. Reality Check28 July, 2010 13:28

    @James: Yes, but this north/south stacked pairing would still require level changes for "back-riding" -- a perfectly valid type of transfer in which you ride back in the direction from which you came in order to reach your destination.

  5. Reality Check: "back-riding" is most likely to take place at express stations, which are likely to have two island platforms to serve all four tracks. At these stations, you would have to execute two level changes (to the mezzanine and back onto the other platform) in order to do this. Though I'd imagine that "backriders" will be a relatively small portion of the market.

  6. @ James

    I don't think that F-S on one level, and S-F on the other would be practical, because they would have to construct platforms on both levels, even at those stations that serve only Caltrain.

  7. Adirondacker1280028 July, 2010 14:19

    The upper platform could be over the lower platform, takes up less space, not by much but it could.

  8. In the stacked configuration why not have side platforms? Then you need a larger width at the station, but everywhere between the station can be done in a narrower width.

  9. @ Adirondacker12800

    That would require an F-S F-S stacked alignment. I can see that making the transition into and out of the stacked arrangement more complex (in other words, pour more expensive concrete for more overbloated and operationally expensive "solutions").

  10. Adirondacker1280028 July, 2010 16:37

    Then put the side platform for the lower level under the tracks for the upper level. Or here's a thought: stop thinking about byzantine construction and dare to take an acre or two of land along the ROW and build cheaper structures or no structures.

  11. @ Adirondacker12800

    "stop thinking about byzantine construction and dare to take an acre or two of land along the ROW and build cheaper structures or no structures."

    Yes, that's hopefully what will happen.

  12. Lipstick for this pig:

    The lower level climbs at 1% for freight. The upper level can climb at a higher percentage.

    Lower level would need to rise to go over San Francisquito Creek and go around the Palo Alto tree. (similar for some other creeks)

    Bicycle and pedestrian crossings between levels can mitigate the barrier effect.

    There is room for the UP barrier wall between freight and HSR.

    In Mountain View the separation would go over/under Castro Street and still make it to clear Shoreline and HWY 237 overpass. (similar for some other crossings)

    Maybe San Mateo can keep the movie theater?

    Half the passenger train noise, and all the freight noise is below grade.

  13. James: I can't imagine this being used for anything but really constrained places, especially those which also require a station, like San Mateo. Even there though, it seems like it might be overkill.

  14. I agree. A quick check of Clem's previous grade studies shows that double stack ruins the grade separations. This is a study in what not to do. Moving on...

  15. I would guess that you can't really reduce horizontal width for drainage. Drainage is tricky that way. I also don't see a way of reducing width for natural gas line easements.

    Cabled easements should be relocated *above* the overhead rail electrification, as is done elsewhere, thus requiring no additional room at all.

  16. Blogger Peter said...

    "I don't think that F-S on one level, and S-F on the other would be practical, because they would have to construct platforms on both levels, even at those stations that serve only Caltrain."

    It would certainly be convenient though. Actually I think if you're stacking, F-S on one level and F-S on the other level is really the way to go; local-only stops would get platforms on two levels and one sideb (no mezzanine needed), while express stops would get island platforms and a mezzanine.