PC Engine Not Running (no Sound) In Scenario But Can Drive

In one of the runs on Caltrain leaving SF at about 1630 and in the rain leaves without the engine sounds. The game thinks the engine is running because it moves but all you can hear is the rain on the cab roof. At the second stop I shut it down and started it again and from then it was fine but that procedure takes five minutes so of course you miss out on on time running.

Paul