Another benefit: The doors can improve the efficiency of trains because they make it more difficult for passengers to hold open train doors.

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It was a competitive spot to claim, he recalls, and they had to be at a certain set of train doors right as they opened in order to get it.

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NFC-enabled devices like smartphones will allow people to go to a restaurant or movie, access their ATM, lend money to a friend, ride the train, unlock doors, and thousands of other tasks with one device.

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The doors banged together, and the train started back.

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But according to the Rail Maritime and Transport (RMT) union, the new instruction tells drivers to use the intercom to ask passengers to close any open doors themselves and to move the train without the visual check.

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At one point while we were filming with one of our main characters, Lefa, the police actually stopped the train while it was between stations and locked all the doors so they could conduct a carriage to carriage search.

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Platform doors can also allow for air-conditioning of train platforms and prevent litter from getting onto the tracks.

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Heavy doors that opened manually by turning a clunky handle have been replaced by electronic doors that open automatically, as soon as the train stops.

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Amtrak has been proactive in recent years in making train stations in large cities ADA compliant, said Lipp, the Open Doors executive, but the smaller, often privately owned stations, have often been slow to implement change.

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