m7zanr160s Posted November 3, 2014 Share #1 Posted November 3, 2014 Why are all these new mid-station signals being put in on the QBL when T/Os aren't allowed to pull in until they all clear? In theory, it's cool because it would allow trains to close in on the preceding train, but if they can't, what's the point? Link to comment Share on other sites More sharing options...
itmaybeokay Posted November 3, 2014 Share #2 Posted November 3, 2014 Why are all these new mid-station signals being put in on the QBL when T/Os aren't allowed to pull in until they all clear? In theory, it's cool because it would allow trains to close in on the preceding train, but if they can't, what's the point? I'm not sure specifically the new signals you're talking about - but even though T/O's can't enter the station until they're clear, timers mid-platform can still help trains get closer together. Fixed-block signaling requires that a train passing a signal at danger at maximum possible speed, with any semblance of working brakes, be tripped and stop safely before striking the train in front of it. If you've got a 25mph timer mid platform, that means that a train couldn't be going 55 by the time it reached the far end of the platform, and as such, the block in front of that signal can be shorter, and the signals approaching the station can clear faster. Also, I'm pretty sure trains can still enter the station if the signal aspect is red and lunar white (or one of the other timer aspects for this matter). As long as the signal shows that it will clear if you slow to the proper speed, I think you're able to pull into the station. I could be wrong on that one, I don't have a rulebook. Link to comment Share on other sites More sharing options...
bobtehpanda Posted November 3, 2014 Share #3 Posted November 3, 2014 Why are all these new mid-station signals being put in on the QBL when T/Os aren't allowed to pull in until they all clear? In theory, it's cool because it would allow trains to close in on the preceding train, but if they can't, what's the point? Possibly for CBTC. CBTC operation does, when international best practices are followed, allow a train to enter as one is leaving. Link to comment Share on other sites More sharing options...
INDman Posted November 4, 2014 Share #4 Posted November 4, 2014 Possibly for CBTC. CBTC operation does, when international best practices are followed, allow a train to enter as one is leaving. No, with full CBTC the only signals one would see would be interlocking signals. The from B'Way Junction to 8th Av only has interlocking signals. Link to comment Share on other sites More sharing options...
GreeneggsnPelham Posted November 4, 2014 Share #5 Posted November 4, 2014 Sounds like they're installing ST signals. A red-over-lunar is a 1-shot GT signal; the ST signals mid-platform are really common. Link to comment Share on other sites More sharing options...
m7zanr160s Posted November 5, 2014 Author Share #6 Posted November 5, 2014 One station that has multiple mid-station signals is Lexington Ave.-53 St., which I think were added to what was already there. It would be cool to see trains close in on departing trains, like I've seen on the LIRR at Jamaica Station. Mainly, it would help with efficiency, though. Link to comment Share on other sites More sharing options...
GreeneggsnPelham Posted November 7, 2014 Share #7 Posted November 7, 2014 ^^ That's basically what ST signals do--they allow trains to close in on each other. To see these in action, go to any express station in Midtown or other busy areas during rush hour---trust me. You'll see a lot! -A Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.