Bus/Train Meltdowns!

Ok Mother's I'm sure many of you have experienced your child having a meltdown or tantrum in a small place like the train or bus. So what do you do? I personally try to ignore it when my daughter is having a tantrum on the bus because, there's no talking to her when she's having one. Sometimes I feel its a no win situation people look at you as if you have no control of your child. Any stories or suggestions?