A proper suburban rail service with two-way all day service would take a ton of riders off the subway network. It would also cut commute times by a third for a lot of suburbanites.
Keithz,
While I support the idea of an S-bahn/RER for Toronto, and would rank it second in importance to the DRL for the GTA, I really think that that should be a
distant second priority. While I think we really need to improve long-distance, rapid regional commuting options, I don't think it's quite the panacea you say it will be.
For starters, the mother of all S-bahn systems, the RER, is not as successful as its proponents would make it out to be. It serves 465 million riders a year. That's more than the entire TTC system, to be sure, but considering that it serves a catchment area of 12 million people, has 590 km of network trackage and has been the recipient of basically the lion's share of rapid transit investment in the Paris metropolitan region for over 40 years, that's not that impressive. It's also not impressive when you compare it against the metro, itself, which has 1.5 billion riders within a catchment area of, maybe, 3.5 million people and has basically only witnessed incremental expansion since the 1970s.
Secondly, this is the RER in Paris. Paris' suburban lines pass through hundreds of town centres with existing walkable neighbourhoods and surface transit links. Toronto's GO network largely passes through postwar industrial parks and sidings. Prior to the RER, Paris' suburban network was served by a legacy network of electrified, grade-separated suburban railways that largely stopped at heavy duty stations that only had to be upgraded. In some cases, all you had to do was rebrand the line and buy new rolling stock. In Toronto's case, practically the entire GO-REX system will have to be built from scratch. Consider the Stouffville line, which basically consists of unmanned shelters for stations along a single track diesel railway line with surface crossings. Everything about this would have to change, and it won't be cheap.
I think that dense metro networks that serve medium-distance everyday travel needs in dense, metropolitan cities are going to win over S-bahns in ridership potential every time. I bet that if you spent $7B on a DRL or $7B on GO-REX run to RER standards, that the DRL will have a higher ridership. Sure, you would argue that it does nothing for suburban commuters (I wouldn't, but let's assume that's the case), but, frankly, winning over suburban commuters - many of whom commute suburb-to-suburb in commutes that transit will never be competitive with, anyway - shouldn't be the MO of transit expansion. I think that it's much more beneficial to build a dense, inner city subway grid than to build a giant, radial network of S-bahn lines. The DRL does this. It not only relieves the Yonge line, but opens up the possibility of traveling to the dense, job-rich and transit-poor areas of Toronto south of Bloor street and outside of the immediate downtown core.
