Rail passengers go through this diversion, losing energy and time (11)

'rail passengers go through this' is the definition.
(the process of boarding a train)

'diversion losing energy and time' is the wordplay.
I cannot quite understand how this works, but
'energy' could be 'e' (physics symbol as in E=mc2) and 'e' is found within the answer.
'and' could be 'n' (common abbreviation for 'and') and 'n' is located in the answer.
'time' could be 't' and 't' is found within the answer.
This explanation may well be incorrect...