escalator       
noun [ C ] uk/ˈes.kə.leɪ.tər/ us/ˈes.kə.leɪ.t̬ɚ/
B2 自动扶梯
a set of stairs moved up or down by electric power on which people can stand and be taken from one level of a building to another, especially in shops, railway stations, and airports
  I'll meet you by the up/down escalator on the second floor. 我会在三楼向上/下去的自动扶梯边跟你碰头。 
 - More examples
 - Sorry but the escalator is out of use; you'll have to take the stairs.
 - I cannot take this pram up the escalator, so I hope there is a lift I can use.