Thursday, April 30, 2009

How Many LRT Stations are Needed Downtown?

I am a bit mystified about the mini-controversy about how many stations should be in the downtown core. The DOTT plan calls for two, as was shown in the Feb. open houses.

I have heard a number of suggestions we might need 3. I disagree.

Each station will be a entire block long - the "long" blocks in the downtown, ie the east - west blocks (the north south blocks are much shorter). Each station will have at least two exits, most likely near each end. The stations themselves will be very deep down. Unlike Toronto, where the subway is just below the street, ours will be at least six stories deep. Some elevator access will be straight up to the surface, which means there will be two access points to each station, about a block apart. So in the downtown there will be at least four access points to the LRT stations (ie, two per station). From a pedestrian point of view, its like having four stations.

But not all access to the stations need be elevator. Escalators go up at an angle, and from the start point at the station can drift a considerable block or more in any direction as they ascend to building level. Thus there might well be two elevator accesses on say, Albert St, each a block apart, and there might also be another access point or two from Slater or Queen or even further away depending on where the escalators come up. If they come up in a building complex, it will be possible (at least during business hours) for users to travel through the buildings for at least another block indoors.

In sum, two stations, with four access points or more, should be offer frequent enough entrances throughout the downtown core. Each station costs about $70 million.


  1. The primary effect of limiting the number of stations downtown is not from a passenger standpoint, but from an operational standpoint.

    As I explain on my blog, the number of trains that can serve downtown at any given time is limited by the number of stations that are downtown. This is because a train can't leave its station unless the next station ahead is able to receive it.

    While you can increase capacity with longer trains, as the plan proposes with ultimately six-car trains, you can't increase train frequency. A networking analogy is the difference between latency and bandwidth.

    Skipping the intermediary logical steps (which are elaborated on my blog), two-car trains coming from Riverside South will not be able to go downtown during rush hour, because they'll need the capacity of the six-car trains to handle traffic going through downtown on every run. The Delcan consultant said this to me in so many words.

    So when our expensive new rail system is built, for all the work done by Southwest councillors to get the Riverside South connection in the plan, their residents will still have to transfer at Bayview. Why don't we just extend the O-Train to Leitrim and get that right now, for only about $40 million?

    - RG>

  2. Leaving aside the question of how many stations do we need, I'm puzzled by the elevator factor. The capacity of a six train HRV subway car, as used in Toronto, is 1500 passengers. The capacity of a LRT car such as the Seimens Combino Plus is about one third at best of the HRV. In Toronto six car subway train can move about 36,000 passengers per hour. These are big numbers but elevators don't carry anywhere close to that capacity or volume. So the question I have is how on earth are that many people supposed to access the subway via elevators? In Toronto that's not a problem for two reasons. One is the subway stations are just below street level and there is ample access from the PATH. Ottawa has neither scenario and our stations are to be six storeys deep. I don't get it.

  3. An additional point about fewer stations in a high-use area like downtown is that there will be larger passenger volumes at those stations than there would be with more stations.

    That translates into more platform congestion and longer dwell times.

    I don't know what is driving the reduction in station numbers, but my guess is the cost of building them as well as the extra time required. Their cost (and time, which impacts cost) is related to the depth at which they are to be built. The generally-accepted assumption prior to the DOTT study was that the tunnels would be bored at as shallow a depth as practicable while the stations would be created as boxes dug down from the surface - a disruptive procedure to be sure and also the reason that Queen St was high on the list so as to avoid disrupting Transitway service. Station and tunnel construction could proceed independently as neither was dependent on the other. Not so with these deep stations; they're to be mined out like caves largely from below once the tunnels are in place.