Sunday, August 13, 2023

LIRR East Side Access Signaling Surprises

When the LIRR's new East Side Access opened to Grand Central Terminal earlier this summer and I was expecting the signaling to follow the pattern of the LIRR's other recent projects with the new reduced aspect signals like G/L that have become the new standard. However, now that cab view videos have become available the new signaling setup came with a few surprises.


Once trains enter the ESA tunnels at HAROLD interlocking they are exclusively presented with transit style 3-lamp signals displaying single light Green, Yellow and Red aspects. Although these two videos can't necessarily reveal all possible operating conditions, the lack of anything aside from Green, Yellow and Red over both straight and diverging routes implies that those are what one gets in the ESA tunnels even with track speeds up to 45mph. It also appears that intermediate signals are provided in the few parts of the route that have significant distance between interlockings.

I suspect that the decision was made to lean on both the track speeds and speed code based cab signals to simplify the ESA wayside signaling based on the LIRR's existing practices before the implementation of the Reduced Aspect Signals. Remember, ESA has been under construction for almost 20 years and the design work was likely completed a decade before the Main Line capacity expansion projects motivated the new signals. A review of the videos shows a combination of diverging routes at the prevailing line speed (15, 30 or 45mph) or sufficient distance between the signal and the turnout for a cab signal code drop to take effect. On the outbound video there appears to be an unprotected slow speed crossover so I am not sure if that would rate Green signals over cab drops or a Yellow approaching a flashing red or what. I made some inquiries and I will post an update if those pan out.

All in all, the signaling is more interesting than an endless string of Green over Lunar and the use of US&S transit style signals is nice, but its unfortunate we didn't get a full set of LIRR "tunnel" signals similar to the Atlantic Ave branch.

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