There are multiple bins on the train, far more frequently than on a street (exponentially more), yet lazy, stinking p***ks do this:
Even back in our younger, dickhead days, me and my pals always cleaned up after ourselves, be it trains, buses or friends' houses/flats/apartments/etc. We never had to tell each other to not be an arsehole in terms of litter as litter was anathema to us all.