Dozens of Japanese train passengers pushed a 29-tonne train carriage away from the platform to free a woman who had fallen into the 20-centimetre gap between the train and platform during the busy morning rush hour Monday at a station north of Tokyo.

The act of heroism was captured by a newspaper photographer, whose photo of the rescue ran in the evening edition of Yomiuri Shimbun, Japan's largest daily newspaper.

A public announcement that a passenger was trapped prompted about 40 people to join train officials to push the carriage, whose suspension system allows it to lean to either side, according to Yomiuri.

The unnamed woman in her 30s was then pulled out uninjured to applause from onlookers at Minami-Urawa station in Saitama, just north of Tokyo.

After just an eight-minute delay, the train went on its way.

Q.