Establishment in railway property everyone enters (12)
I believe the answer is:
installation
'establishment' is the definition.
(I've seen this before)
'in railway property everyone enters' is the wordplay.
'railway property' becomes 'station' (I can't justify this - if you can you should give a lot more credence to this answer).
'everyone' becomes 'all' (all people).
'enters' is an insertion indicator.
'station' placed around 'all' is 'stallation'.
'in'+'stallation'='INSTALLATION'
Can you help me to learn more?
(Other definitions for installation that I've seen before include "Art exhibit in gallery" , "The making of equipment ready for use" , "Positioning" , "A setting up; equipment so set" , "Apparatus positioned" .)