[updated December 20 below…]
There has been some speculation that the next generation of streetcars/LRVs for the TTC may use pantographs for power collection. If the new lines for the Transit City proposal are to provide a true rapid transit solution, then without a doubt we will see pantographs on those lines. Click here to see the new page on comparing trolley poles with pantographs.
Ideally, a single type of vehicle would provide the most flexibility, but there will be some overlap as the CLRV and ALRV fleets will continue to be used as long as it is practical to do so. On a loop of track, both trolley pole and pantograph operation can co-exist. The problem comes when you reach a track switch or crossing. Trolley poles require a frog to guide it through properly, while pantographs only have to slide under it. I am not aware of crossings and frogs that allow trolley poles to pass and at the same time cannot snag a pantograph. There may be such a beast, and please forward an example of this, but I have not seen it.
I had thought that existing streetcar routes could be upgraded one at a time as new fleet using pantographs arrived. The CLRV and ALRV fleet would be relegated to the remaining trolley pole routes as the fleet and number of routes still using trolley poles dwindled. There is still the issue where one route crosses the other and how to get vehicles back to the car-house. Other cities, such as Pittsburgh and Melbourne, have converted from trolley poles to pantographs as a total conversion that involved retrofitting existing trolley pole vehicles with pantographs.
Having one type of vehicle may be a moot point. The TTC may end up placing an order for new LRVs that have doors for boarding only on the right side as all current operations have loops to turn around at the end of the line. I strongly suspect that the Transit City plan will require vehicles with doors on both sides. It would be more practical and less costly to turn-back using crossovers instead of loops. Loops require land, while crossovers require little, if any, road-space. Crossovers also make it possible to operate a section of the line on a single track while maintenance is performed on the other. With loops, you have to close part of the line completely and bring in replacement buses. Furthermore, having doors on both sides makes it feasable to have less costly stations with centre island platforms at some locations instead of separate platorms for each direction of travel.
Getting back to the issue of pantographs, there is a fair bit of the TTC’s streetcar overhead that would work as-is with a pantograph-equipped vehicle under it, but there are enough areas where changes are needed. I plan to add to the Trolley Pole vs Pantograph page in the next month or two with some information on what changes would be required on the TTC. For an example of what an ALRV looks like with a pantograph, check out this page on the Transit Toronto website with photos of ALRV prototype 4900.
UPDATE - December 20
A comment was posted on Steve Munro’s website here containing a response to a letter sent to the TTC. In a nutshell, trolley pole operation will be retained at this time for the current streetcar network (and likely for the new waterfront projects) but may eventually be converted to pantograph. The new vehicles for the existing streetcar network will be uni-directional with doors on the right side only.
The Transit City network will adopt a pantograph catenary system to allow higher speed and bi-directional operation. The new vehicles for Transit City will therfore have doors on both sides.