Many of its stores are either located in front of a train station or are directly connected to one, making them very easily accessible with lots of foot traffic. (simplybitcoins.com)
With a partial vacuum, some air will begin to build up in front of the train as it travels, which would normally slow it down. (fortune.com)
Would you push someone in front of a train if that would save five others? (newscientist.com)