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Re: Full Shutdown of L Train to Be Halted by Cuomo

Posted by Stephen Bauman on Fri Jan 4 11:02:33 2019, in response to Re: Full Shutdown of L Train to Be Halted by Cuomo, posted by AlM on Fri Jan 4 08:28:03 2019.

1. Skip 1st and 3rd Aves when single tracking. 1 Ave is important on weekdays but less so on weekends. I'd say skip Bedford too because it's a short walk from Lorimer, but that would overload the platforms at Lorimer. Maybe the time from USQ to Lorimer could be reduced to 6 min.

According to yesterday morning's rush hour real time feed, some actual travel times between the stations were 15 seconds less than scheduled. This would reduce turnaround time to 14 minutes.

Skipping a station would reduce time by 15 to 30 seconds for each station. The 15 seconds is dwell time and the other 15 seconds comes from braking/acceleration time. However, the crossover switch position negates any braking/acceleration time gain at 3rd and Bedford Aves. This would account for 30 sec @ 1 Ave and 15 sec each at 3 & Bedford Aves. These savings could reduce the turnaround time to 12 minutes and no margin.

The distance between Union and Wythe Aves along N 8th St is about 3600 feet.It also involves crossing under the BQE at Metropolitan Ave. That's already been identified as a dangerous intersection. (If 3600 ft is a "short walk", I'd advocate abandoning the SAS.)

2. Run 2 trains in a row in the same direction... maybe you could manage 7.5 tph

I did mention what I proposed was the most wasteful way possible. The service level depends on headways as well as the turnaround time. I proposed running 6 trains in a row @ 90 second headways a few years ago. That would have provided 12 tph. A more modest service level would permit fewer trains in a row and longer headways.

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