After a couple of minutes, the train ground to a halt (in an entirely controlled manner) and we sat there, just North of Kings Sutton.
A quick check of a couple of on-line reference sources showed that, just in front of us was a First Great Western train going from Banbury to Oxford. In front of that was a Cross Country train heading from Manchester to Bournemouth.
The driver came on the PA and told us that a train in front had broken down and that a rescue locomotive was being sent to assist with moving it. Somewhat erroneously I assumed that the issue was with the FGW train.
As there was nothing else to do, I let loose on Twitter and discovered something slightly unusual had happened.
It transpired that the Cross Country Service to Bournemouth (train 1O18, which I had earlier seen pass through Leamington Spa) had actually taken a 'Wrong Route'.
What this means is that the signaller had set the points and signals for the train in the wrong direction. Now, obviously, a train driver cannot actually steer a train but, nevertheless one would hope that the driver would not have knowingly taken the wrong route.
The reality is that if the train was traveling at say 75 - 100 mph on green signals, the driver would probably not have had time to stop before the incorrectly set signal.
My working assumption is that the Cross Country train diverted off the Oxford Line and, instead started to head towards Bicester North, on the line usually used exclusively by Chiltern Railways passenger trains. I have no idea how far the train got, or what it did to reverse back up the line to resume it's correct journey.
What I can say is that the incident delayed the Cross Country train by 35 minutes between Banbury and Oxford. It then eventually arrived into Bournemouth 34 minutes late at 1745. From what I can see, the train then set off just 3 minutes later (and 3 minutes late) for a 302 mile trip to Leeds, which it achieved without incident.
The train I was on eventually arrived into London Marylebone 31 minutes late.
Given the thousands of train movements that happen throughout the day, over thousands of sets of points, I am amazed that this sort of incident doesn't seem to happen more often.
I've pasted below the eventual timings of the trains involved / delayed over Aynho Junction, plus a copy of the tweet I received advising of the true cause of the incident.
Stay happy. Stay safe!
As a footnote, I ought to say that at no time were any men, women, children or animals put in any danger by this incident. The signalling system is designed to ensure that safe gaps are maintained between trains, wherever they may actually be going to. The fact that our train came to a perfectly smooth and controlled stop is evidence of this.