If that's the criteria for an odd working, I could be typing all day
Perhaps the oddest thing that happened to me was, due to a failed train south of Kings Norton, my HST to the West Country was diverted via the Kings Norton avoider, Camp Hill, Birmingham New St
non-stop, Kidderminster, Worcester and back on to the main line.
Another diversion I encountered was being held at Grindleford on a CT 158, I was going toward Sheffield (with Max) but due to a problem ahead we avoided Sheffield, taking the sharp curve at Dore and went straight to Chesterfield. Fortunately a HST turned up not long later to take us to Sheffield.
I've been on a Class 87 out of Euston which had a broken windscreen, and terminated at Bletchley after running at a fairly slow speed (50mph?) on the slow lines for a while. I've also been on a Class 87 that failed to call at Rugby due to a failed windscreen wiper on a Pendolino blocking the only usable platform (at that time). But, like your 377 crossing tracks, that's not terribly exciting.
A far more exciting event occured when I made sure I was the last to board a GC HST for London via Cambridge, ensuring my place by the window immediately next to the Valenta on a hot summer day (the other pax wedged into the vestibule were more than happy for it to be open!). We then had an additional diversion via Church Fenton, Knottingley and Askern, which was a nice bonus!
If planned diversions count, then a class 37 via Glasgow Central low level on the Scotrail sleeper in the Spring of 2006, and a class 50 to Fishguard via the Swansea and District
and Barry on 2 September 2006 have to rank quite highly (this was the first time the trolley bloke had
ever sold literally
everything from the trolley. Jim bought the very last item, a packet of Nobby's nuts, on approaching Cardiff!). If only I had not had to go back to York, I believe there was then a non-stop class 37 to Rhymney in passenger service after the 50 arrived. 3 1/2 years ago? I remember it like it was yesterday but sadly the railway has got a lot worse since then.