44 North
Senior Member
Tunnel cost is $50M/km. https://www.thestar.com/business/20..._million_contract_to_tunnel_eglinton_lrt.html
Say $75M with inflation. If you tunnel an extra 3 or 4 km to a better TBM extraction site, you might just break even right there. Then when you want to remobilize to extend the subway, no TBM's are required at all - just excavation contracts for Stations (and emergency exits). It would likely cost double (or more) to remobilize TBM equipment to extend the tunnel those 4 km.
If we use the Toronto method of building subway every 50 years, it may not make sense. But if you intend to extend the subway in 5 or 10 years, then doing the tunnel now makes sense.
Did you notice how MTO tends to build the substructure wider than required to allow for future widening. This eliminates the costs of remobilizing for pier construction in valley.
Can't help dwelling on the word wider and thinking if it would make sense using three tracks. Slim down the trains, increase the tracks. One express track southbound in the AM only stopping at the key stations, which switches to express northbound in the PM. Other two tracks are normal all-stop. Torontonians are urban and more than adaptable, we could handle spicing things up a bit to more mimic the complexities of a system like NYC's. RL could be Line 7 - A, B, C services (local, express inbound, express outbound).
Not sold on using 100m trains for a new subway into the core like what Metrolinx is peddling. But if three tracks over its whole length any loss in train capacity is made up in overall line capacity and thus a bit more palatable.