Maybe I can provide a bit more context re: Montreal.
Montreal's metro throughput is not gated by the tunnel capacity. It is gated by the amount of trains in operation. Adding additional cars on the 'already full line' would increase the line's capacity. Neither the orange nor the green line are close to full.
The issue with the orange line extension isn't that the lines are full. It's that 1) subway costs are heavily subsidized at the municipal and provicial level, 2) they were extended to Laval which funds the STL, not the STM, and 3) there was no revenue or cost sharing agreement between Laval and Montreal to subsidize the STM in proportion to the burden placed on the STM by Laval riders.
This issue with cross-subsidization also lies at the core of the municipal agglomeration which occurred in Quebec metropolitan regions.
Montreal won't consider additional subway expansion not because of financial and infrastructure cost reasons, but because of political ones, much in the same way that internal negotiations regarding the dual super-hospital projects were intentionally sabotaged for political reasons.
Montreal's metro throughput is not gated by the tunnel capacity. It is gated by the amount of trains in operation. Adding additional cars on the 'already full line' would increase the line's capacity. Neither the orange nor the green line are close to full.
The issue with the orange line extension isn't that the lines are full. It's that 1) subway costs are heavily subsidized at the municipal and provicial level, 2) they were extended to Laval which funds the STL, not the STM, and 3) there was no revenue or cost sharing agreement between Laval and Montreal to subsidize the STM in proportion to the burden placed on the STM by Laval riders.
This issue with cross-subsidization also lies at the core of the municipal agglomeration which occurred in Quebec metropolitan regions.
Montreal won't consider additional subway expansion not because of financial and infrastructure cost reasons, but because of political ones, much in the same way that internal negotiations regarding the dual super-hospital projects were intentionally sabotaged for political reasons.