Going back to the original post, and based on my experience as a rider of light rail (and growing up with streetcars then the Metro & BART in SF) ... the train operator normally can't cancel the crossing gates - the train doesn't control them, the train signal system and, usually, backup track circuits do. As long as the signals and grade crossings are interconnected and there's a train between stations, grade crossings will remain closed at least between the train and the next station. If the train isn't moving and sits long enough, the grade crossings should eventually time out, but that doesn't always happen depending on how things are hooked up. Then, if it's a busy line with lots of trains in both directions, a train stopped at a station may be holding all the grade crossings closed until *its* next stop, and things can overlap producing general chaos if nothing moves.

I would expect that, with a broken-down train, there would be some initial effort going on to fix it (Sac RT operators have gotten pretty good at quickly "rebooting" trains in hot weather), to move it to the next station, or to get people off and onto buses. In any case, there are people who don't necessarily know how to behave around the broken train, and it's probably not a good idea to have things running on the other track until the situation is under control.

As for derailments, yes, I can understand that light rail management is more bus-centric - sometimes but not always. Part of the delay might be that light rail people don't get as much practice cleaning up minor derailments as the old streetcar people did. So everybody stands around scratching their body parts and "securing the area" while waiting for the "big hook" truck with the airbags, jacks, etc. to arrive from the shops across town. Plus, not many streetcars ran on long chunks of private r/w with open track like a real railroad - which makes jacking and moving things more difficult. And of course Murphy's Law dictates that most of these incidents - derailments or breakdowns - will occur during rush hour, especially in the morning (though for some reason BART breakdowns seem to prefer the evening rush) so the delays can last all day. Finally, there's always the question of damage to the switch where the derailment usually happens - call out the track inspectors and if the problem is more than trivial then, yes, a contractor probably will have to be called. In our case, it took almost a week to fix the switch so it could be operated at normal speed again (35mph), and we were riding buses for a couple of days.