How Big a Hole Do We Need?

At its meeting on July 9, the TTC approved purchase of four tunnel boring machines from LOVAT Inc. for construction of the Spadina Subway extension at a cost of about $58-million.  There was considerable discussion about this expense from the point of view of whether any could be recouped after construction, or what commonality there might be with Transit City requirements.

Various tidbits came out during the questions to staff from Commissioners.

The Sheppard tunnels are 5200mm inside diameter, whereas the Spadina tunnels will be 5400mm.  The larger bore is required both to meet current fire code, and to allow trains to travel through curves with sufficient clearance.  (The Sheppard line is, pardon the pun, rather boringly straight.)  The larger tunnel size adds about $35-million to the cost of the 6km of bored tunnel on the Spadina line.

Transit City tunnel size will be determined by the dynamic envelope required for its cars and for the overhead power supply.  These tunnels may not be the same diameter as those on the Spadina subway, but more to the point, the construction period for both Spadina and Eglinton overlap and using the Spadina machines for Eglinton will delay that project.  It is conceivable that the Richmond Hill subway, if funded, might inherit the machines.  Otherwise, the TTC expects to be able to sell them for about 30% of their original value.

This question will also affect the Sheppard tunnel at Don Mills, a short but necessary piece of work to get under Highway 404.

The TTC has canvassed the world market for second hand tunnelling machinery, but none which has the required bore diameter and soil condition design is available.

In a conversation after the meeting, I learned that although the single large bore tunnel (13m) proposed for Eglinton might be feasible, this large tunnel greatly increases the cost of removing spoil (earth and rock) because the tunnel structure is much larger than would be the case for two single tunnels.  In turn, this begs the question of how much of the Eglinton line will be built cut-and-cover so that it is not dependent on the availability of tunnel boring equipment.  We shall see in the fall when the next set of community meetings come around for the Eglinton corridor study.

Restructuring the Queen Car

The TTC Agenda for July 9 included a report on Queen streetcar operations.  Most of this deals with line management techniques, and is discussed in the preceding article on this site.

For the period October 18 to November 21, 2009, the TTC will experiment with splitting the line in one of two ways.  The specifics have not yet been decided.

  • Split the route at Humber Loop into the original 507 Long Branch and 501 Queen routes.
  • Create two overlapping routes with Long Branch cars operating east to Church or Parliament, and Queen cars operating west to Bathurst or Shaw.

Implementation of an overlapped service is constrained by the number of available cars as well as by track layouts and the location of electrified switches for turnbacks.

There are arguments to be made for either configuration, but the first one does have the problem that if Queen service is disrupted in the west end, the link to Long Branch will be lost as most Queen cars will turn at Sunnyside.  Conversely, an overlapped route will force anyone travelling from west of the overlap area to east of it to transfer. Continue reading

Queen Car Operation Update

At its meeting on July 9, 2009, the TTC considered a staff report about operation of the Queen 501 streetcar service.  This reviews various attempts at line management and scheduling as well as their effects on service as measured by short turn counts as well as the number of wide gaps between cars.

For the period October 18 to November 21, 2009, the TTC will experiment with splitting the 501 into two separate overlapping routes, although the exact termini of the routes is not yet decided.

The Queen car has been the source of many complaints about service quality, and I have written several articles here examining the actual behaviour of the route in detail based on TTC vehicle monitoring data.  The most vocal complaints arise in The Beach, and much effort has focussed on that end of the line, but problems also exist on Lake Shore.  Concerns to the west emerged during recent public meetings on the proposed Waterfront West LRT line where providing basic, reliable service today was more important to residents than a new LRT service in the distant future. Continue reading