This is a common profession in Japan. Train pushers (or oshiya, as they are called) work subway stations during rush hour to help passengers fit into the train. These guys were first introduced at the Shinjuku station – the busiest transport hub in the world, according to Guinness World Records. Now they can be seen at all major train stations in Tokyo.
Naturally, the main requirement for an oshiya is physical strength. It is said that they are usually recruited from the ranks of former sumo wrestlers. They also need to move fast enough to work two doors of the same car. Not a good job for a couch potato!