Is a staff privilege card valid on Grand central ?
I have just been issued with a grey pass valid for concessionary travel only on Northern Rail.
I lost my Blue one same as agency workers.
I think people are getting confused.
Northern Rail staff get free travel on Grand Central/Merseyrail/Greater Anglia/Scotrail (later) (and residential on TPE), BUT:
You're not Northern Rail staff by the sounds of it.
I would imagine you are either a cleaner or work for G4S/revenue protection. In which case you can only use your pass to get into/out of work with Northern, and no other TOC.
Blue Pass = Staff with full travel benefits
Grey Pass = Non-staff with no travel benefits
If you don't have the ATOC "75%" PRIV card, and you aren't in the Railway Pension Scheme (DB), then you won't be able to use your pass anywhere else.