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Washington Metro returns to computer controlled trains
I’m not super familiar with WMATA, but they have one employee on board each train whether or not the propulsion is operated by the computer, correct?
Computer-driven trains may be applied to mainline freight and intercity passenger railways later this century. My paediatrician’s prediction is coming true when he told me as a small child that trains will be autonomous someday.
Yes, James. There was previous to 2009 and will be an operator in the cab during automatic operations. I ride the Red And Yellow lines daily, and although WMATA is constantly criticized, Metro’s trains and buses are usually clean and efficient, and much better than the alternative of sitting in my car for a savings of only 10-20 minutes per commute.
How come the operator didn’t hit the brakes when it became clear that the computer was going to crash the train into the other?
@Mr HUTCHESON the crash location was on a curve and had very limited visibility.
I lived in the DC area back in the 70’s and 80’s and read a trade journal description of Metro’s signalling system. Basically it uses the same system as with many freight (and Amtrak Northeast Corridor) cab signalling systems, but uses audio frequency carrier signals instead of the 100Hz systems used by the other lines. The higher frequencies are consitent with the shorter “blocks” used by Metro, and enable the dispensing of insulated joints at most locations (except for places like interlockings). The problem here was that Metro had mixed detecting equipment from different vendors and did not properly maintain them. This caused incidents of the track sensor (the modern equivalent of a track relay) to malfunction which resulted in a false clear condition for that segment of track, even though a train in that track circuit should have shunted the signals in the rail. . The field logic, therefore had a ll the blocks in advance of the faulty circuit to give some non-zero speed cab signal to any train approaching. The problem with the track circuits were known, but due to lack of urgency were not remedied untill Metro’s (and the unfortunate passenger’s) luck ran out with this accident.
There is a large red button in the control booth of Metro trains known as “the mushroom” which is the emergency shutdown/brake. On the train that crashed in 2009, the operator had deployed the mushroom but the stopped train was not all the way to the end of the platform. Also, the 1000 series cars telescoped. Those cars were suppose to be removed from service but are still running today.
The biggest trouble was multiple vendors providing the sensors. The trouble is if you have a sole source vendor and they go belly up you are stuck. On the other hand they also had a problem with keeping up with maintenance of the system Both go hand in hand. As for the lone operater on the train , when it is in computer controled mode the operater only opens and closes doors. They would have to over ride the controls to run the train.