But is the intent to disrupt the train? No, it's to hold it long enough to get on board. The law is written such that you'd have to want to disrupt the service for nefarious reasons, not to board it.
Here in Europe disruption to board the train is enough to get police called on you and have them fine you, the fine grows with every minute of disruption. Not a crime, but definitely not legal. Stopping a moving train without necessary cause is criminal.
Very often the conductor will let you board a train late by signalling you with hand or speaking... But disobeying the conductor's signal whistle is where you step into potential illegality, because the train might (and sometimes really will) start moving that same moment.
All of this doesn't apply to city public transport - trams, metro etc. But it does apply to trains passing through the city.
