Bidirectional Signaling for Express Tracks

[CenSin]

I know the MTA had once considered bidirectional signaling for Queens Boulevard to allow three tracks to run trains in the peak direction during rush hours as an alternative to building more tunnels. But after taking the a few times during the weekend, I’ve come to realize that the benefits could also extend to track work scenarios.

 

Take the Brighton line for instance, the MTA could close down both southbound tracks, and run southbound trains on the northbound express track. The transfer between trains going in diferent directions would be cross-platform, and track workers could have the entire space on one side of the right-of-way to work with. For the Brighton line, all the switches necessary for this arrangement are already in place (except at Prospect Park, where the switches between the express tracks should be moved to Parkside Avenue).

 

Other lines which this is possible:

• Fulton Street (with signaling work)
• Queens Boulevard (with signaling work and switch reconfigurations)
• Central Park West (with signaling work and minor switch reconfigurations at 59 Street–Columbus Circle)
• Broadway (with signaling work and installation of switches north of Prince Street)
• 7 Avenue (with signaling work and minor switch reconfiguration at Chambers Street)

[Sparen of Iria]

Even if QBL was running that, there would not be enough track capacity to get trains out because you'd be forcing a theoretical 90 TPH on one track, which is impossible.

[CenSin]

Even if QBL was running that, there would not be enough track capacity to get trains out because you'd be forcing a theoretical 90 TPH on one track, which is impossible.

I guess that's why they gave up on that. But it's still a useful mode of operation for track work. Shut down two tracks on one side, and run trains on the other. The Nassau Street line runs like this from Canal Street to Essex Street.

[Sparen of Iria]

That's very true, regarding track work. The question in the end is whether or not it is cost-effective to maintain an extra set of infrastructure solely for this purpose.

[LTA1992]

I guess that's why they gave up on that. But it's still a useful mode of operation for track work. Shut down two tracks on one side, and run trains on the other. The Nassau Street line runs like this from Canal Street to Essex Street.

That's not exactly true as the signal system on that track should have been completely remodeled for outbound traffic only.

[bobtehpanda]

The main reason it isn't done anymore is because it would be very expensive. Finding express/local setups for subway signalling is hard enough due to the limited use of such track setups around the world; finding one that can do bidirectional express tracks is an order of magnitude more difficult since that introduces so many possible conflict points. As it is the MTA has a giant signalling replacement backlog, so I can't imagine they can spend money on optional things anymore.

[R3216068E]

Well if you ask me the signal infastructure is a big problem on 8 ave line the and can crawl on the express because of signal maintenance along the 8 av line the signals on the express track can be big pain if the weather is not nice

[CenSin]

The MTA could get work done faster though with trains mostly out of the way. It’d be like a semi-FASTRACK. On the West End and Sea Beach lines, for example, running trains on only 1 track per line (Coney Island-bound on West End, Manhattan-bound on Sea Beach) provides track workers with 2 or 3 track widths of contiguous space and allows trains to move along without flagged zones.

 

While the true cost of bidirectional signaling isn't known to any degree by us forum-goers, it's at least cheap enough that the MTA maintains a third track where there is space for it. With 2 bidirectional express tracks, it’d be the same as maintaining 2 of those middle tracks commonly found elsewhere in the system.

 

My point is, the bidirectional signaling for both express tracks on four-tracked lines may simply pay for itself with increased efficiency, faster speeds in work zones, and—thus—improved public relations.