As I'm writing this Matt is playing the scenario in GCC where he's driving a Class 314 to rescue a failed train and bring it to the depot, and it's interesting because here in Italy I've never seen an EMU rescuing a failed train, and I found the reason in an official document of our rail operator (I'm translating it, so there might be some mistakes): "in some predetermined places there are one or more locos standing-by in case of a failed train, the availability and modality of rescue are reported in the service schedule" Actually, it has happened that a rescue loco just couples to the stranded train and that train then goes on onto his journey (with a delay obviously), and suppressing the train is the most extreme option, so in that GCC scenario what would have happened is that after Matt coupled, the train would have continued towards Glasgow stopping at the various stations and then, brought to the depot. If this service is realistic, it's interesting to see the difference in the british system - granted GCC is not in a large distance main line concept, so I can see it being different. THIS IS NOT MEANT AS A CRITICISM TO GCC OR THAT SCENARIO! I'm just curious about real life procedure, I think in the UK I've seen a 37 (and apparently a 91!) hauling a dead 755. No idea about Germany. Interestingly enough, very recently we did some testing to see if a Trenitalia (national rail operator) high speed train can push or pull an Italo (private rail operator) trainset and vice versa because in case a high speed train fails on the line, the procedure would be for the preceding or following train to push/pull it.
Well, just a couple of months ago, I saw a BR101 pulling a 'dead' ICE-T. Even though, I'm not sure, if this consisr will go the whole way to the original terminal. I suppose, it would only go to the next station, where the passengers can change to a subtitutional train (most likely some IC-coaches with a loco).
Usually it would be a loco, but that depends on stock availability, and where the failed train is, with the situation simulated in game, there’s a train not only blocking a busy station, but a junction, so whatever available unit suitable for the tow would be dispatched. As for continuing the service with the failed train in tow, that would almost always be avoided, but could be possible depending on the nature of the failure.
I’ve seen GWR do it once on a late night last train of the day, they towed a failed train and operated it but there was obviously about a hour or so delay on this train then, I can’t be sure what the fault was but I know the toilets were taken out of action for the rest of the journey. I’d assume being the last train of the day they had no other option and had to run it somehow.