It's been an entertaining trawl through this thread, and I quite agree that a minor anachronism or geographical substitution should not diminish enjoyment of a film or tv programme - particularly when many of these play fast and loose with the laws of physics or biology in much more incredible ways! It can be a shame that some productions that have made great efforts to create a period setting are undone by the railway aspect, but as in the many examples discussed upthread, this rarely has any real impact upon its enjoyment.
It is also easy to understand that no TOC is going to want a drama featuring a train crash to involve their brand, and heritage DMUs or MK1 stock on a preserved line is about as near as we are going to get.
Silent Witness for one, and I'm sure at least one other British detective tv show in recent years, has had to adopt this approach. The result will be acceptable to the vast majority of the population, who are not only not train enthusiasts, they will not even be regular train users.
One series where trains seemed to play a major role was
Crossing Lines, an unintentionally-funny show made for the American market about a pan-European crime agency, who were based in The Hague but managed to reach any corner of Europe by train in a just of a couple of hours. It was filmed almost entirely in Prague, which stood in for every other European city as required, apart from one episode where the lack of a palm-fringed coastline in Prague did actually require a visit to Croatia, which probably blew most of the budget for that series!
In one episode, the villain is identified from his seat number being compared to the passenger manifest which apparently all express trains in Europe have
. If this might have been just about credible, the scene was shot on the upper deck of one of ČD's City Elefant suburban trains, which very clearly had no seat numbers visible. Surely a better attempt could have been made to get right something integral to the plot?
Finally, the most jaw-dropping moment I've ever had regardng trains on screen. Unable to sleep, I got up early one morning a few months back and, with little on offer, began watching one of the UFO-related "documentaries" that lurk among the digital channels. I forget the details, but the incident involved a US freight train that had (allegedly) come to grief due to an encounter with a UFO. There was a bit of simple CGI showing what was supposed to have happened, then the big reveal of the damged loco...
I was absolutely gobsmacked to be presented with a still of 81 016 with its cab stoved in after the 1982 Linslade accident! Considering the driver was killed, I found this shockingly bad "journalism" in very poor taste.