What are you on about? Give me some numbers? How many loco failures this year?
92 failures this year are probably in single figures (or at least the ones we know about!) I'm also pretty sure this was the first time this year that one failing (or any of the electric locos for that matter) has resulted in a full cancellation or anything more than an hour's delay.
All of these problems are going to result in a significant backlash next year. It is easy to argue at present that the "trains are old and unreliable" and that next year we will have new ones.
There will be new carriages next year but the locos will be the same. If we have come to a position where we don't have any locos which can travel a few hundred miles to Scotland and back from London a few times, and expect them to provide heat, lighting and power all at the same time without breaking down then there is something very seriously wrong.
Someone along the line is going to point out that in most other countries, that they have locos which can run thousands of miles and do all these things.
The GBRf 92s are being overhauled and extensively modified to improve their reliability on the sleepers. Six have had the "mods" done already, one is in Loughborough with them underway - and three are due to have them done in due course. The one that failed on Sunday night is one of the ones that hasn't had the "mods" yet (although incidentally is
usually a pretty reliable one).
Let's also not forget the 92s were designed to haul sleepers - and between them are covering c.1,500 miles per night, 6 nights a week largely without incident.
Since all the work at Wabtec/Brush the 92s have been a lot more reliable. They will breakdown - as all locos do - and GBRf are usually very resourceful at getting the train from A to B even when this does happen. (I believe there was a specific unfortunate set of circumstances on Sun night that meant a replacement loco wasn't feasible - but won't bore you with the details.)
As mentioned before several times on this thread, due to the profile the Sleeper has, and the fact one failure on one leg can scupper several others,
any (major) failure gets a lot of publicity.
However, I don't think your pessimistic view of the traction is really backed up by recent overall performance, nor the considerable work that has gone in to improving the 92s.