Does NJT (and MNCR WOH) idle their diesel locomotives or shut them down overnight or during long turnarounds (the set used on train 52 is in Hoboken for 4 hours before being sent out as train 47). I believe Amtrak keeps them idling overnight, but I think NJT shuts them down.
If you have ground power to plug into,you normally shut down the HEP genset and the prime mover,unless you have a bad set of
batteries,or a way colder then normal weather forecast.