Holiday period problem for US rail travellers? (4)
I believe the answer is:
noel
'holiday' is the definition.
(I know that Noel is a holiday)
'period problem for us rail travellers?' is the wordplay.
I cannot really see how this works, but
'rail' could be 'el' (El train, short for elevated railway) and 'el' is present in the answer.
The remaining letters 'no' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
(Other definitions for noel that I've seen before include "Christmastime" , "Christmas carol" , "Coward - Christmas" , "Christmas, esp. in carols; boy's name" , "Coward who wrote and acted, d. 1973" .)