F-Line to Dudley
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You'll have to wait for the Green Line Transformation study to come out in 2019. FCMB has been presented with a few slides of what they're tackling, but still too early for any meaty details. That report is what's going to ID the signal speed-ups, the new Type 10 specs, and other sweeping system mods. Short-term they'll be tweaking signals to close up some slow zones. Full signal replacement and conversion to new technology is going to be stepped out on the later stages of the agenda because of the delicate nature of dispatching in the Central Subway and risk that a speed-enforcement or CBTC system will screw with default headways. To even project what the options are they have to have precise modeling of what schedules the longer trains will keep with all-doors Proof-of-Payment, surface signal priority, etc. Those are numbers they're still crunching, so premature to be making any predictions on what/when for the signals. But they aren't standing still, as the D reconstruction is replacing old copper signal cable with new high-bandwidth fiber optic that'll be able to feed a future signal system, and North Station-to-GLX will have it with ongoing construction.
Red/Orange as widely reported are getting total signal recalibration after the new, faster-accelerating cars have arrived. Optimizations will not go live until after all old cars have been retired, because the optimizations won't work well with mixed fleets of mixed performance profiles. It'll still be the same ATO system--tweaked--but they are likewise installing fiber end-to-end on both lines in all places that don't yet have it. That will give them the bandwidth to be able to transition later to a future signal system of their choice, like CBTC/moving-block. CBTC is mainly a central dispatch computer investment; the field hardware installs are pretty sparse if you already have the fiber run. Thus, they're getting the most labor-intensive field work done now and buying themselves a little more flex to evaluating the back-office technologies for the future.
Blue's signal review is happening as part of the BL Resiliency study for sea level rise. The current mechanical trip-stops are very vulnerable to water because of the heaters and motors installed at every signal block, and all the associated feeder cables that could get fried by a water intrusion. With hundreds of these trip-stop installations and supporting infrastructure across the line, Blue signals are the #1 most flood- and storm-vulnerable infrastructure on the rapid transit system. So Priority #1 for flood protection is getting rid of all that extra electrical/mechanical cruft, and likewise doing a complete copper-for-fiber replacement of communications cable (where fiber doesn't corrode or short). Red/Orange-style ATO would eliminate an enormous amount of Blue's signal hardware...and requires only periodic placement of low-voltage track circuit transmitters. CBTC does even better since its transmitters are wireless and can either be mounted well above track level or encased in water-tight plastic at track level. That makes Blue particularly attractive as the T's CBTC test bed. It's entirely possible they do it there first, then port it to Orange/Red afterwards. This Resiliency study is likewise in its infancy, but should provide some good discussion grist (albeit not as squarely performance-oriented as the goings-on with the other 3 lines) next year.
Red/Orange as widely reported are getting total signal recalibration after the new, faster-accelerating cars have arrived. Optimizations will not go live until after all old cars have been retired, because the optimizations won't work well with mixed fleets of mixed performance profiles. It'll still be the same ATO system--tweaked--but they are likewise installing fiber end-to-end on both lines in all places that don't yet have it. That will give them the bandwidth to be able to transition later to a future signal system of their choice, like CBTC/moving-block. CBTC is mainly a central dispatch computer investment; the field hardware installs are pretty sparse if you already have the fiber run. Thus, they're getting the most labor-intensive field work done now and buying themselves a little more flex to evaluating the back-office technologies for the future.
Blue's signal review is happening as part of the BL Resiliency study for sea level rise. The current mechanical trip-stops are very vulnerable to water because of the heaters and motors installed at every signal block, and all the associated feeder cables that could get fried by a water intrusion. With hundreds of these trip-stop installations and supporting infrastructure across the line, Blue signals are the #1 most flood- and storm-vulnerable infrastructure on the rapid transit system. So Priority #1 for flood protection is getting rid of all that extra electrical/mechanical cruft, and likewise doing a complete copper-for-fiber replacement of communications cable (where fiber doesn't corrode or short). Red/Orange-style ATO would eliminate an enormous amount of Blue's signal hardware...and requires only periodic placement of low-voltage track circuit transmitters. CBTC does even better since its transmitters are wireless and can either be mounted well above track level or encased in water-tight plastic at track level. That makes Blue particularly attractive as the T's CBTC test bed. It's entirely possible they do it there first, then port it to Orange/Red afterwards. This Resiliency study is likewise in its infancy, but should provide some good discussion grist (albeit not as squarely performance-oriented as the goings-on with the other 3 lines) next year.
