This is our 'watch dog'--railroad firemen that follow the train, watching for signals from the engineer, fireman(on the train) or brakemen that there is a problem--beyond fixing by 'on board personnel', that assistance is needed,come closer and help. There is always a car that goes out before the scheduled train even leaves the station(Durango or Silverton) to double check track conditions---cause even in the best of weather, rocks fall, etc. that will cause problems. Lots of safety issues taken care of so we, the passengers, can enjoy our day.