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| Re: The Washington Metro's 26 TPH limit (1406155) | |||
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Re: The Washington Metro's 26 TPH limit |
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Posted by Sand Box John on Tue Aug 23 23:13:06 2016, in response to Re: The Washington Metro's 26 TPH limit, posted by fdtutf on Tue Aug 23 21:53:35 2016. You misread my comment. I didn't say "most railroads"; I said "most of the railroad," by which I meant WMATA's railroad.OK, however from my prospective that point is irrelevant. The numerous merges also play havoc with throughput, and the only line that doesn't have that kind of merging is the Red Line. The issues at the junction revolves around timing, as in timing the approach to the junction to properly execute the weave with the trains from the other route. WMATA has a subsystem within its train control and signaling system that is designed to handle that, Automatic Train Supervision (ATS). It is designed to alter the speed of trains (speed up or slow down) and dwell times (lengthen or shorten) to maintain proper spacing. Mind you if the railroad get really jacked up ATS becomes of useless. Pay no attention to the naysayers that say the points in the junction turnouts can't be moved quick enough to allow the following train to enter the interlocking. Fact is the turnouts can be reset within seconds of a train clearing the interlocking. I have stood at the south end of the lower level Rosslyn platform and heard the switch motor begin to move the points before the tail lights of the train that just cleared disappeared around the curve. The same applies on the upper level, the points can be reset and the signal cleared while a train is discharging and boarding passenger at the platform. John in the sand box of Maryland's eastern shore. |
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