Why Do Streetcars Bunch Up?

Over at torontoist, Adam Giambrone responds to a question about bunched service outbound from Mimico on the Lake Shore with a collection of the usual lame TTC excuses about irregular service.

This is getting tiresome, and it is distressing to see the TTC Chair spouting so much of the party line from TTC management.  The reasons for irregular service, according to Giambrone, are:

  • Bunching caused by minor variations in the time spent at stops and traffic lights.  This applies to frequent routes where the headway (as cited by Giambrone) is fairly close to the variation in delay times.  The last time I looked, the best scheduled service on Lake Shore is every 8’40” on Saturday afternoons, rather worse at other times including peak periods.  Minor delays at stops do not account for bunching.
  • Traffic congestion.  Yes we have heard this before.  The point, as we have seen in many of my analyses of route operations, is that congestion is manageable, and bunching should only occur when there is an actual blockage of service.  See below.
  • Traffic signal delays.  Yes, signals are being changed to give priority to transit vehicles, but this has already been done on much of the Queen route.  Major intersections, where traffic engineers feel that transit priority could be counter-productive by its effect on cross-street traffic, run on their regular cycle.
  • Surge loads.  Yes, they happen, but they don’t explain routine bunching.  Moreover, on Queen, the line uses all-door loading at major stops.
  • A shortage of supervision.  See “traffic congestion” above.  The TTC feels that if it can just put a small army of route supervisors in the field with better technology to let them know where the cars actually are (see Next Bus display at Spadina Station when it works), they can manage the service better.  As some comments in the Torontoist thread point out, there is a big problem with operators leaving terminals more or less when they feel like it causing ragged service, and little seems to be done to manage the gaps and bunches out of the service.  This happens on many routes.
  • Short turns, larger vehicles, more service.  This bullet in Giambrone’s presentation is, to say the least, unclear.  We know that busy routes have delays and need short turns, although changes in the management style for the 501 eliminate most of the need for this tactic (a point completely missed in the article).  Larger vehicles will help provided that the total capacity of the route is also increased.  Queen has suffered for decades with the effect of a reduced number of cars providing allegedly equivalent capacity.  Between cases where short cars are running in place of long ones (and they get late because they can’t handle the demand) and the larger impact on waiting times of missing cars, the change to wider headways has been a disaster for riding on the line.  There is no indication that the TTC understands this problem.

There are three fundamental problems with service on Queen and on Lake Shore (where the original reader comment arose):

  • The Long Branch 507 should never have been amalgamated with 501 Queen.  The route west of the Humber River has a large amount of local demand, but the decline in service quantity and reliability of the merged route has never been acknowledged.  The TTC just does not understand that service is important on the outer parts of lines, not just at Yonge Street.
  • The amount of service on Queen is insufficient to provide a reliable headway and capacity for demand.  The TTC may point to declining ridership over the years, but this is not reflected on other parallel routes like King or Dundas.  The irregular service drives away riders.
  • Route supervision leaves a great deal to be desired.  For clarity I don’t just mean the guys standing on the street corners making notes on their clipboards, but the whole strategy of how a line and its operators are scheduled and managed.  The TTC is working on this, but changes are slow to come.

I have begun detailed examination of Queen route operating records for December 2008 and January 2009, and will be publishing results from this work here soon.

GO Transit Buys CN Weston Subdivision

GO Transit announced today that it will purchase the CN Weston Subdivision for $160-million.  The line in question runs from roughly the Strachan Avenue grade crossing to the junction with the CN York Subdivision at Steeles Avenue.

CN and VIA run comparatively few trains (3 and 6 respectively) each day on the line, although VIA has planned improved service in this corridor for some time.  GO plans greatly expanded service both in frequency and in destination (extending to Kitchener), and this corridor will also host the Blue 22 Airport link should that line ever get beyond the drawing boards.

By purchasing the corridor, GO will not only have better control of train operations, it will be able to retain ownership of the substantial improvements needed to accommodate all of the new services.

The press release is silent on the matter of funding.