Interlining makes sense for areas where you have lots of traffic. Interline through downtown, and branch in different directions in the burbs.
Like Eglinton where the expensive underground portion is shared by branches going to??
Maybe one branch along Dixon and one along Eglinton West??
Maybe one branch along Eglinton East and one up Leslie??
It looks like Toronto does not follow this “ruleâ€.
Interlining through the lowest-use section of Line 1 makes no sense, nor would I think there'd be the capacity on Line 1 to support it, where they are already planning to fully utilize the capacity south of Finch West.
But it could make sense if it is utilizing tunnels that are under-utilized. YUS does have capacity to the north, since every other train short turns at Downsview. To the north, there is the capacity of these YUS trains not heading north, and to the south, it could be possible to substitute a Sheppard train in place of a short-turn train.
Running to the transfer point at the Downsview Park GO station might make sense - but you'd still need to run a double set of tracks, as you can't be running a Line 1 train every 2 minutes, and then add in a Line 4 train every 6 minutes (or less, given the likely lack of demand west of Yonge)
Just don’t do every 6 minutes because it won’t divide evenly.
Westbound Sheppard trains every 4 minutes – alternating north and south.
Northbound YUS trains every 2 minutes – alternating north, short-turn, east, short-turn.
Southbound YUS trains every 4 minutes – alternating south and east.
Bit of new track needed, but all constructed on the SW corner of Dufferin – Sheppard with open cut.
I'd think a better solution in an infinite world would be to keep running west from Allen/Sheppard (Sheppard West station aka Downsview Station) under the airport to an additional station at Sheppard/Jane and then north on Jane to Jane/Finch to intersect the LRT. Why run 2 lines together, instead of running them in different places.
Mostly because it is less costly to re-use the tracks for both lines than to build a whole new route.
And the main question it leads to, is what would be the ridership. I have a hard time thinking that it would even be the existing 5,000 an hour on the Sheppard subway, west to Yonge in AM peak.
I’m not sure. I could easily see people continuing to Downsview and south since they would have a guaranteed seat and not transfer. There would also be those going to YorkU and eventually Vaughan Centre.
As Pasternak pushed the TTC to actually study the feasibility of the "North York" relief line, perhaps we'll see some estimated numbers for subway ridership - which should be similar if the service terminated at Downsview or ran through to Vaughan.
This means that minimal riders would continue to YorkU – the largest single transit draw north of 401.