Depends. Birmingham UK commuter trains during peak hours tend to be full, and full of fairly middle class people as the fares are much higher than the bus. Late at night, yes, a little more care is needed.

I have about an hour round trip on a train, and I can get a few interactive whiteboard screens or a handout written in that time (I'm a teacher).

I use a refurbished laptop so if any funny stuff starts, I just hand it over.