No railroad is going to let a long train tie up its main track for hours while all other trains remain stopped as a sole employee aboard struggles with an unplanned event such as an air hose separation 75 cars behind the locomotive. He might get the train tied down, analyze the problem, fix it if possible, and then release all the hand brakes the same day he started.
Tom,
I haven't worked for a railroad but wouldn't it be dangerous to leave a running engine unattended for any length of time?
Doug