Train doors have handles on the inside. They are stiff so that they cannot be opened accidentally.

火车车门内侧有把手。把手很紧，这样就不会被意外打开了。

《柯林斯英汉双解大词典》

Please stand clear of the train doors.

本班列车即将开出，乘客请勿靠近车门。

youdao

That was a dangerous thing to do, whipping in like that just as the train doors were closing.

当火车门正在关闭时像这样窜进来是危险的。

youdao

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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