All of the proposed Kitchener Line stations label the 4 tracks as 2 UP Express and 2 Kitchener Line, with the platforms only accessing the Kitchener Line pair. This is very concerning because it would widen the speed differential between the fastest and slowest services on that pair of tracks, reducing capacity and reliability.
So based on these plans, we would have big lumbering loco-hauled GO Trains stopping every couple kilometres on their 100 km trip to Kitchener (or stuck behind other trains that stop), while small quick-accelerating UP Express EMUs pass through those stations without stopping on their 25 km trip to the airport.
Here is the current ranking of the corridor's services by average speed
1. VIA
2. GO Express
3. UP Express
4. GO Local
Rather than having an "UP" pair (medium speed) and a "GO" pair (high speed and low speed), we should have an "fast" pair and a "slow" pair. And because the fastest services will all be continuing straight at Pearson Junction, the "fast" pair should be on the east, while the local pair is on the west.
Instead of operating UP Express as a quasi-express service that's still much slower than VIA or GO express trains, I think it makes more sense to combine the airport service with the planned Bramalea EMU service to form a metro-like local service at an interleaved 8 trains per hour on the western pair of tracks, while the eastern pair of tracks carries the intercity, regional and commuter express services free from interference from slow local trains.
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