110mph vs freight on semi-shared track

As I understand it, the main crushing blow that makes it so expensive to go beyond 79mph is the in-cab signaling requirement. Or, more precisely, the cost of adding it to freight trains so they can run on the same track as 80-110mph passenger trains too, since it's an expense the host railroad is going to refuse to pay for since it's not critical to most freight operation.

I was thinking, though... if an existing railroad had only a single track rated for 79mph, but a second track were constructed that was up to 110mph standards, and the necessary fixed signal infrastructure and crossing upgrades were installed, would the FRA allow 110mph operation on the new track if non-ICS-equipped trains were simply prohibited as a matter of railroad policy from using or crossing the 110mph tracks during the day?

Taking it a step further, could the railroad adopt a policy of having variable speed limits on the "good" track, with the dispatcher electronically indicating a 79mph speed limit in the vicinity of crossover tracks only when a slow train were operating in the area? Or is that beyond the capabilities of current signal infrastructure (or worse, the laws behind it)?

miamicanes wrote:As I understand it, the main crushing blow that makes it so expensive to go beyond 79mph is the in-cab signaling requirement. Or, more precisely, the cost of adding it to freight trains so they can run on the same track as 80-110mph passenger trains too, since it's an expense the host railroad is going to refuse to pay for since it's not critical to most freight operation.

I was thinking, though... if an existing railroad had only a single track rated for 79mph, but a second track were constructed that was up to 110mph standards, and the necessary fixed signal infrastructure and crossing upgrades were installed, would the FRA allow 110mph operation on the new track if non-ICS-equipped trains were simply prohibited as a matter of railroad policy from using or crossing the 110mph tracks during the day?

Taking it a step further, could the railroad adopt a policy of having variable speed limits on the "good" track, with the dispatcher electronically indicating a 79mph speed limit in the vicinity of crossover tracks only when a slow train were operating in the area? Or is that beyond the capabilities of current signal infrastructure (or worse, the laws behind it)?

In all it sounds cool I would suport the idea but I think that even if all this were done with signals and crossings and all it would be more of an expence to keep up the maintaince on locomotives and cars being used. Not all locomotives are geared to run at same speed Tonnage would make a difrence and the condtions of the cars would more than likley play
a roll as well. Some cars not all cars in a unit according to the rules can only be run at a certin speeds to control rocking and outher things.

100m.p.h. crossovers have been installed befor on varyed coummter lines befor just can't see it being done on a fraght railroad with the expence of fixing it. Althow strangley enough the Lehigh Valley did have crossovers built to take trains moveing at 60m.p.h. on most of there trackage. verses the NYC main line on up threw Conrail had crossovers ment for 40 mp.h.