Staging *something* along the corridor seems intuitively smart, yes.
But I would question whether crews can be staged in a useful way. VIA has to schedule people to maximise the amount of work they do within the very strict hours of work rules imposed by Ottawa. Adding contingency time to shifts would lower productivity. Having crews staged at midpoints would not work, as they would be conspicuously idle 95% of the time. And, when they are needed, weather and other factors might mean they couldn't reach the scene of the problem. Having crews "time out" on hours is hard to avoid when delays happen given their fairly tight scheduling.
The same is true of trains - VIA's need to cycle trainsets productively means that any delay cascades, as clearly happened recently.
Rapid-response of standby trains and spare board personnel from the existing terminals is possible, but the same productivity issues arise and travel time to the problem would still be problemmatic - if, indeed, a standby train could thread the needle thru blocked freight and passenger trains to reach the problem. Once you have a standby train, maybe it's better deployed to fill in whatever gap in the cycling the non-availability of the stranded train creates.
- Paul