Fairly often, parts of rail cars or track department equipment will come loose and be dragged along the tracks. This often results in extensive damage to wayside Automatic Train Control (ATC) equipment.
Usually, this causes substantial delays — particularly if impedance bonds or “loops” are involved. Both are used for train detection and to transmit speed commands. When an impedance bond is damaged, it appears as though the adjacent track circuits are occupied. This means that every train approaching the damaged bond(s) must come to a complete stop (as if there were another train ahead). The operator must contact Central Control (OCC) and request permission to continue. Once they receive permission from OCC, they proceed in manual control at no more than about 12 mph. Of course, if there is a radio ‘dead spot’ where the trains are coming to a stop, things can get really ugly.
Here is a photo of a bond that is in reasonably good shape:
Here is a photo of an impedance bond (the older GRS “Wee-Z” bond) that was snagged by something dragging under a train:
Below is a ‘marker coil’ that got hit hard. Marker coils tell the train when it is approaching a station and how far it is to the center of the platform:
A couple months ago, after I had retired, the track dept. had a little mishap while moving some rail. From what I understand, the equipment that carries the rail derailed but no one was aware of it for several minutes. You’d think that OCC would notice a string of track circuits going down (showing occupancy) and staying down long after the track dept equipment had passed. I think the final tally was 8 bonds that had to be replaced. I imagine this was reported to the public as a “technical problem”.
Needless to say, accidents happen. There is no way to prevent all instances of dragging equipment but this sort of damage seems to happen way too often at Metro. Part of the problem is that those that are responsible for the damage do not have to fix it or pay for it. There are never any repurcusions that I’m aware of. The attitude of management and workers alike seems to be, “Oh well. Sh*t happens. What’r ya gonna do?
Meanwhile, my former coworkers are out on the tracks risking their lives fixing the mess that someone else made while passengers sit and wait in trains that are often crowded and uncomfortable.