Someone to deal with it in less than three hours, while keeping all the affected passengers informed?????
So:
1) Train fails
2) On board staff try to identify and fix the fault
3) They cant so they call control and ask for a fitter to be dispatched
4) Said fitter boards his van in the depot which is liable to be some distance from site
5) Fitter drivers to site ( in a speed limited van no doubt !)
6) Fitter tries to fix train
7) He cant so he asks control for an assisting loco
8) Due to the nature of the privatised railway everyone runs about like mad trying to find a loco, then find a loco that can actually couple to the stranded train, then find a driver who signs the route, then after finding him realise he has insufficient hours left, then find another driver with hours on the clock, get everyone to agree who pays, sort out a path then send the loco on its way, essentially the wrong way down a one way street
9) Staff on site, in conjunction with HQ maintenance types bodge up a fix, perhaps using brown paper and a boot lace from a passenger and train limps away and voilà the line is open.
Now whilst I am sure you know best and without wishing to cause offense how do you propose things be done quicker? On board spares? Helicopter transfer? Crewed, spare, locos every 17 miles?
I am sure control would love a copy of the Haynes Railway Operations manual that you all seem to think exists which allows you to turn to page 45632 appendix ii sub paragraph zz which indicates that a total loss of air can be fixed within exactly 43.45 minutes and the train rolling within 45. Unfortunately the world aint like that.
Now, at no point do I not suggest that being stuck on one of these trains is a massive pain and a total inconvenience and liable to create anger and frustration. That said the same problems happen in your car or at the airport.
Communication is clearly the key to keeping passengers informed but the kind of communication you want is simply not possible. You want to know, almost instantly, how long you will be stuck. That simply cant be done in anything like the speed people want.