I hope the OP comes back and update the description.

Being groped/molested in often public places

the act of public groping or molestation, most notoriously on crowded commuter trains.

The act of fondling or touching another person in a sexual manner. Rarely consensual and often takes place on a train or a bus.

it's not specifically train, just any kind of public molestation, i think?

I agree with Ookami on this one.

I Think is not limited to transportation (train,bus etc), but also applies to crowded public place such as concert, elevator, swimming pool, sauna room, hot springs, japanese festival etc