Doing signal repair along this railway line? (6)
I believe the answer is:
siding
This clue could be a double definition.
'doing signal repair along this railway' is the first definition.
'siding' can be an answer for 'railway' (siding is a kind of railway). I am not sure about the rest of the definition.
'line?' is the second definition.
(I've seen this before)
Can you help me to learn more?
(Other definitions for siding that I've seen before include "Railway marshalling area" , "location for shunter" , "Short stretch of railway track off the main line" , "Stretch of railway used to store trains" , "Railway spur" .)