Someone mentioned the police on here.
I served in two forces - the Met and Greater Manchester.
In the Met, bobbies used their warrant cards on the Underground and on Central London rail services for free and this was for both commuting to and from work and also rest days. It also covered buses aswell.
What I do remember about the Met policy was that the free rail travel was only covered for sixty miles outside of Central London. I worked with quite a few officers who lived in the home counties - one lived in Northampton and commuted in everyday to Euston and he then used the Underground to get to Kensington and did not pay anything. In fact the use of both trains and buses was widely encouraged by bosses as firstly if you were on duty in full uniform you were of course a deterent for troublemakers.
When I served down there in 2005/06, the station I was based at had strong rules about you travelling to and from work in part blues (wearing your trousers and white shirt underneath a casual jacket) because of things like professional image and self security off duty - what happened to Lee Rigby in 2013 is a prime example. However, if using your warrant card on public services while wearing 'civvies' you were still expected to deal with any incidents that broke out, the danger was that having no radio with you made you quite vulnerable and I've seen a few cops over the years try to deal with stuff off duty with the best of intentions and have landed up in hospital for their troubles.
To the best of my knowledge, I never had to deal with anything and when travelling from Euston to the North of England I always paid the full fare rather than blag my way as far as Milton Keynes for free!!!!!
Moving on to GMP - I know officers are widely encouraged to use any public transport while on duty because once again it is a welcoming site for Drivers, Conductors, or Revenue Protection Officers to have a visible presence on board one of their services. This includes the Metrolink which sadly is still plagued with issues like anti social behaviour.
Throughout most of my service for GMP I worked on the outer divisions so I never needed to use public transport to get to and from work. There was however occasions when I had to attend Manchester Crown Court to give evidence and you usually wear formal atire for these occasions rather than your traditional uniform (to be honest I never liked GMPs black cycling tops and combats which look appalling and unprofessional). Considering this is technically work related - I still had to pay the full fare but police officers then had to submit travelling expenses forms with proof of the journey attached (the actual ticket being clipped to the form). Petrol receipts and pay & display tickets were also submitted for these things.
Certainly the Met policy on using your warrant card could very well have changed since I left. There have certainly been a few officers facing Misconduct hearings in recent years for fare avoidance and have lost their jobs because technically it is a criminal offence. It is simply not worth it.
Just regarding rail employees for one TOC using another TOC's service - would speaking to a member of staff at the station ticket office be worth while prior to boarding any train? I would be inclined to seek advice from someone in the station before going near a train about whether I would need to pay anything. I'm very interested about this as I'm presently applying for a Arriva TOC but may have to use a First Group TOC from time to time if I get the job?
CJ