I do wonder though how long is waiting on a train in between stations without any hope of the train moving would be acceptable to passengers? Looks like people were on board for around an hour? before getting rescued and obviously in different circumstances(e.g if this happened in hot weather) then issues could start to develop like passengers fainting and even detraining themselves(Which of course happened during the infamous GNR farce in 2015).
I wonder why coupling a train to another is a massive safety issue with passengers on board whilst on the national rail network, this does happen quite often and all you experience is a slight movement as the trains couple together. Thankfully this breakdown did not occur on a hot day or in a tunnel section.
If something similar happened in hot weather detraining still isn't the best option. What would be best in that situation is opening the right hand door leaf to let cold air in. It will annoy the driver but after 30-45 minutes of waiting it's highly likely you will be evacuated. People actually detraining onto the tracks is another extreme, and in the GNR case I think it was more one person complaining, releasing the doors and evacuating and everyone else just following along. They had little regard for safety, and just wanted to get to the end of the run to see their friends/family. If trains had of still been running they wouldn't of gotten to see their friends/family at all.
If the driver is keeping the passengers updated then most people will be fine and will wait, if someone needs medical help they can dial 999, use the passenger assist button, or call metro control (the number is inside the train).
A couple of reasons, trains can't be safely dispatched, faults can spread depending on the circumstances so you'd then have 4 metrocars needing rescued. Some metrocars now dislike talking to each other and as such they can't be paired/coupled up.
