Dallas runs trains slower, and at certain temps, stops them completely above ~104 sustained for ~>4 hours because the rail can/will buckle due to expansion. I t

Dallas runs trains slower, and at certain temps, stops them completely above ~104 sustained for ~>4 hours because the rail can/will buckle due to expansion. I think they also do a stop travel when the temp gets below a certain temp as well. It's not unheard of, and not a bad idea when it comes to public safety and potentially derailing a commuter train in downtown or whatever your worst case scenario is.