We have been fighting this issue for a couple of weeks and throwing parts at it as it is intermittent and I have to much info to throw here, but here is the start:

Car intermittently shuts down in the basement (terminal landing)

We have the following faults:
13 - M contactor dropped while moving
14 - BC dropped while moving
18 - STP to ST safety string opened while running.

We have replaced every contact except for LRU and LRD which looks in line with this input. I plan to change today We have changed I/O boards. Any insight to this issue?