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Re: BMT Canarsie Line history question.

Posted by Stephen Bauman on Fri May 22 18:47:27 2020, in response to Re: BMT Canarsie Line history question., posted by randyo on Fri May 22 16:45:22 2020.

Many oof the els on both the IRT and BRT/BMT did not have signals on the lcl tks so the M/M operated on sight which allowed closer headways.

It did not. Signals have a negligible effect on service level capacity (or minimum headway), unless the signals are very poorly designed. Here's a link to a talk I gave last year at the Transit Camp about what determines service level capacity.

https://public-transit-time-bucket.s3.amazonaws.com/share/SafeMinimumHeadwayOnASingleTrack.pdf

I kept the math simple. One of the people in the audience was a design engineer from NYCT's signal department. He did not contradict me.

The two sections of track that had the highest actual, documented service levels were the Brooklyn Bridge at 66 tph and the Williamsburg Bridge at 52 tph. Both had signals. Their secret was that the operations merged 2 tracks into 1 and then diverged back into 2 without an intermediate station.

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