Crossword Genius

They may go up the steps and under the train (5)


I believe the answer is:


I'm a little stuck... Click here to teach me more about this clue!

'they may go up the steps' is the definition.

I cannot understand how the remainder of the clue works.

Can you help me to learn more?

(Other definitions for rails that I've seen before include "Wading birds - dysfunctional person has come off them" , "Barriers of horizontal bars and supports" , "Tracks or barriers" , "secretive birds" , "Metal bars of a barrier" .)

I've seen this clue in The Times.
Want a hint initially instead of a full solution? Install my app