Celebrity finds railway like a night sky (6)
I believe the answer is:
starry
'like a night sky' is the definition.
(I've seen this in another clue)
'celebrity finds railway' is the wordplay.
'celebrity' becomes 'star' (a star is a celebrity or famous person).
'finds' says to put letters next to each other.
'railway' becomes 'ry' (abbreviation for railway).
'star'+'ry'='STARRY'
(Other definitions for starry that I've seen before include "Like a clear night sky" , "with many famous actors" , "Like the Milky Way" , "'Of cloudless climes and - - skies' (Byron)" , "Shining brightly" .)