Wednesday, January 6, 2010

More Turkey Talk on Tunnel

In a previous post on the downtown Ottawa transit tunnel (DOTT) I mentioned a presentation I saw at Transit Committee on Dec 16th comparing the surface and tunnel options.

The Committee has provided me with a copy of the powerpoint presentation by the Downtown Coalition. Here are the key slides, including the $100 million dollar saving figure. This figure might mean the tunnel saves $100m over a surface rail option, or that the tunnel saves $100m over the current BRT operation, its unclear to me. Their conclusion however remains that the tunnel has a reasonably quick payback period. Double click pictures to enlarge.


  1. I don't thank you enough for bringing stuff like this to wider attention (well, my attention at any rate). Thanks again for all your hard work. Mayor Larry should hire you to do his PR work, as you're certainly more articulate than anything I've seen out of the Mayor's office.

  2. Thanks for posting this.

    The last slide is disingenuous. The $100M annual operating savings is the current plan's savings against the existing BRT system, yet it is presented on a slide touting the difference between surface and tunnel LRT. As I explained in a previous post, there is not enough room for $100M of annual operating savings between surface and tunnel LRT because the distances are too short for the small marginal differences between them to amount to much overall. The extra LRVs represent about 18% more LRVs than already budgeted ($325M worth at $5M each for 65; $60M buys 12 more, or 18%); from that we can assume from that a roughly 18% increase in operating costs of surface vs tunnel LRT. That of course is assuming that his 18% figure is actually accurate, which I don't think it is. This 18% applies to the entire 12-13 km run, not to the ~2.2 km difference between surface and tunnel (much of the 3.2 km tunnel is under the transitway alongside the Canal, so there should be no speed/time difference between the two options there), even though it is only in this ~2.2 km where the surface LRT will be going slower.

    Suppose that the 12 km of the tunnel LRT project can be covered at an average speed of 40 km/h. The time taken for that is 0.3h. 18% more than that for surface is 0.354h, so the entire difference of 0.054h has to be assigned to the ~2.2 km of surface running downtown. The tunnel LRT covers this 2.2 km distance in 0.055 h (@ 40 km/h) and the surface LRT therefore would cover it in 0.109 h (6m32s) at an average speed of 20 km/h. This is stretching credulity, but it gets worse when the speed assumption of the tunnel LRT is revisited.

    Bear in mind also that the downtown is also likely to be the slowest section for the tunnel LRT as well and an average speed of 40 km/h probably won't be maintained here. If, for the sake of argument, the tunnel LRT maintained an average speed of 30 km/h in the 2.2 km downtown section, this would have the result of lowering the surface LRT speed to something like 17 km/h. For reference, the #2 maintains an average scheduled speed of 15-16 km/h between Westboro and Preston in the morning peak period. It's quite a stretch to believe that surface LRT, in dedicated lanes with traffic signals optimized for them and level boarding at platforms would move along at the same sort of speed as the #2 on Richmond/Wellington/Somerset.

    Some of Hume's other claims are puzzling too. The $200M, which is an inflated number from the N-S LRT, should already include utility relocations, and if surface LRT were limited to one street rather than two these relocations would be reduced. Construction delay costs of $80M would amount to something on the order of 10% of total annual transit costs for a period of three years (see above calculations but replay them out systemwide ... or don't and just think about it and realize how preposterous it is). The actual surface LRT costs would probably be closer to $250M (ok, call it $285M), for a difference of upwards of $450M. That's enough to buy us an extension to Baseline in the west... tunnel or Baseline... tunnel or Baseline...

    I don't think Hume and friends sanity-checked their c

  3. Anyone who thinks that the "collapse" of the Transitway system in the downtown is still in the future, doesn't take the bus.

    This "collapse" — as defined by the inability of the streets to handle the bus and passenger load — happened at least 15 years ago, if not more.