One of Bart's problems in the early days was that the voltages in the track circuits, if you can call them that, was too low to puncture even a small amount of dirt and/or corrosion, and that the trains weren't heavy enough to make good contact with the rails and keep them clean. For a long time Bard ran with scrubbers, which were metal blocks that rubbed the wheel treads to keep them "shiny" enough to make good contrat with the rails (and sunt the track circuits).

Several years ago, the BNSF had similar problems in the Valley, although they don't want to admit it.