Debatable then whether you should be "blabbing" about it or posting a clip on YouTube. What is to say there's not something in that video which gives away the date and time, which a manager could then use to start disciplinary proceedings against the driver concerned?
The link above to the Edson accident provided fascinating reading and, while the unauthorized person in the cab was not a factor, there could be other circumstances where you are. For example, a driver could have a SPAD (pass a red signal) and whereas that might result in a sanction short of dismissal normally (unless he makes a habit of it), if it came to light there was an unauthorized person in the cab it would likely lead to dismissal. I work in the UK rail industry (not as a driver) and even where we can have officially sanctioned cab rides some prefer not to simply on the grounds that if anything did happen, you could be held directly or indirectly culpable as a distracting influence.
In fact it's true to say the cab of a loco, at least in the western world, is almost as sacrosanct a location as an aircraft flight deck these days. So, glad the OP enjoyed the ride and seem to have got away with it - but you might want to reflect on the potential consequences and whether it is really wise to publicise your experience.