crs1026
Superstar
^One of my reservations with the Havelock routing is that double tracking would be so costly that it may never be justified. Having said that, while I once assumed that any HxR line ought to be double track, I have become a fan of not taking that step. VIA's very effective use of its Ottawa-Brockville line is Exhibit A in that.
For HFR, assuming a base service plan of hourly service in each direction, with trains running at roughly 100 mph, trains would need to meet every thirty minutes at spacings of 50 miles apart. In a perfect world, one would only need a passing siding or short length of double track every 50 miles. For the Toronto-Ottawa segment, that implies at most 4-5 "default" passing points to deliver that basic HFR spec. Ottawa- Montreal only needs one or two.
To get flexibility, one would at minimum need to add sidings to adjust meets as timekeeping requires. The traditional steam-age standard was rougly 7 miles between sidings. On the Toronto-Ottawa line, restoring sidings where they once existed may be the cheapest strategy as the terrain will often make another location more costly. That siding spacing ensures there are no long waits for opposing trains, and it's amenable to any upgrades to track that increase speeds in slow zones.
Having built that basic design, there would be very low payback to double track.... except..... each potential meet adds minutes to the schedule...one must assume that VIA is allowing several minutes for up to 5-6 en route meets for its basic HFR spec.
The question then becomes, where can you add double track to save minutes, and how difficult is the terrain at that location? Cost may vary widely depending on location.
It makes sense to take those "default" meeting points and add double track for a few miles at each end, using higher-speed turnouts (as @smallspy has suggested). That would ensure meets do not force either train to slow down, let alone wait. However.....if track speed changes, the double track may not be in the right place, as the optimal meeting points have moved.
Bottom line - the business case for double track has to consider impacts on track speed, and scheduling. The payback may depend a lot on the construction costs at specific locations. One wonders how much scalability there truly is to this route.
- Paul
For HFR, assuming a base service plan of hourly service in each direction, with trains running at roughly 100 mph, trains would need to meet every thirty minutes at spacings of 50 miles apart. In a perfect world, one would only need a passing siding or short length of double track every 50 miles. For the Toronto-Ottawa segment, that implies at most 4-5 "default" passing points to deliver that basic HFR spec. Ottawa- Montreal only needs one or two.
To get flexibility, one would at minimum need to add sidings to adjust meets as timekeeping requires. The traditional steam-age standard was rougly 7 miles between sidings. On the Toronto-Ottawa line, restoring sidings where they once existed may be the cheapest strategy as the terrain will often make another location more costly. That siding spacing ensures there are no long waits for opposing trains, and it's amenable to any upgrades to track that increase speeds in slow zones.
Having built that basic design, there would be very low payback to double track.... except..... each potential meet adds minutes to the schedule...one must assume that VIA is allowing several minutes for up to 5-6 en route meets for its basic HFR spec.
The question then becomes, where can you add double track to save minutes, and how difficult is the terrain at that location? Cost may vary widely depending on location.
It makes sense to take those "default" meeting points and add double track for a few miles at each end, using higher-speed turnouts (as @smallspy has suggested). That would ensure meets do not force either train to slow down, let alone wait. However.....if track speed changes, the double track may not be in the right place, as the optimal meeting points have moved.
Bottom line - the business case for double track has to consider impacts on track speed, and scheduling. The payback may depend a lot on the construction costs at specific locations. One wonders how much scalability there truly is to this route.
- Paul
