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Re: Doppler based RF signal activation?
Author: Dr Zarkoff
Date: 10-01-2016 - 21:59
>I can't say precisely how they're doing it, but SacRT does have crossing gates/signals tied into its block signal system on PRW (and street running in some spots).
>RT doesn't actually have block signaling for train control;
OK, I'm confused. Either the RT has block signals which control train movements or they don't. There's no half-way about it.
Crossing track "circuits" are usually separate from the block signal track circuits, although the RT could have some tie-ins to crossing gate positions so a particular signal didn't clear (to green) before the gate is all the way down.
The crossings probably don't have predictors, which are expensive, so the crossing circuits are keyed to occupancy time rather than train speed. If so, then you can't exceed certain speeds in stations, which would rule out express and limited service.
>RT doesn't actually have block signaling for train control;
OK, I'm confused. Either the RT has block signals which control train movements or they don't. There's no half-way about it.
Crossing track "circuits" are usually separate from the block signal track circuits, although the RT could have some tie-ins to crossing gate positions so a particular signal didn't clear (to green) before the gate is all the way down.
The crossings probably don't have predictors, which are expensive, so the crossing circuits are keyed to occupancy time rather than train speed. If so, then you can't exceed certain speeds in stations, which would rule out express and limited service.
