The OCD in me demanded that I do an amateur back of envelope attempt at a three-track occupancy plan for 15 minute local and hourly express service plan on LSW.
What it shows is - with the current schedule, it's possible to interleave express and local trains westbound from Union, provided there is overtaking capacity (the third track) roughly between Clarkson and Burlington. Clarkson is about as far as a stopping train can get before an express train following (leaving Union just before the next local) catches up.
Looking at the eastbounds, however no overtaking is necessary because the existing stopping schedule is tighter eastbound than westbound.
So, a 15 minute stopping schedule with an hourly express schedule fits into a 3-track LSW.
If the express only runs hourly, there is a window of about 38 minutes when the "westward overtaking track" between Clarkson and Burlington isn't occupied by GO. That's enough time to slide a VIA train through once an hour. However, if the express headways are changed to 30 minutes or less, as will happen at peak, the capacity for express eastbounds is limited to one or maybe two movements, following in between the stopping trains. There is no option to use the third track in the counter-flow direction. This is where a fourth track would be needed.
The Hamilton trains would meet pretty much at the West Harbour station, which happily is where GO has double tracked - using only one track between Aldershot and Bayview.
Overall I was surprised at how well the 15/60 pattern fits the existing track design. (GO clearly knows best!)
- Paul
