And yeah 281 running on 285hp rather than 570hp - did the acceleration / speed suffer a lot then...?
As far as I recall from when I looked on RealTimeTrains afterwards it was only a few minutes down (no more than 5) at Whitland and Narberth (where I left the train) and had made up time by Tenby (so maybe the traincrew managed to get it going again, although it might just be down to the lack of information updates on the Pembrokeshire routes). In any case the 150 wasn't significantly late as I managed to film the HST coming the other way (which would have passed the 150 at Tenby) not far off schedule.
I get the 769 problems, but surely LHCS could be rented? It happened on Windemere in the summer.
Or if Northern start releasing 142s before Xmas, get those. Of course the sticking point will be who stumps up the cash.
Do Porterbrook own anything that is fully-servicable, off-lease and capable of working on W&B routes without infrustructure modifications? If so, and we've already paid Porterbrook to lease the 769s from August 2018 (which I think was the original date), is there any scope to say "we've paid, now if you aren't going to deliver the goods (769s) give us alternative goods (Pacers?) in leiu"? Or have Porterbrook simply given ATW and WAG their money back for the first few months of the lease that won't now be happening? I which case that money could be used to lease something from an alternative ROSCO.
Is the track on the ValleyLines continuously welded rail?
There are probably some mark 2 aircon rakes out there that could be used; the issue is that the DBSOs won't work with a reliable diesel loco, so if you want to avoid top&tail these not alot you can do. About the only terminal stations on the franchise I can think of that have run-round loops now are Carmarthen, Blaenau Ffestiniog and Holyhead I think. Carmarthen isn't much help because nearly everything there goes into Swansea where a loco can't run round. I suppose a Carmarthen-Tenby shuttle (using the passing loop to run round) might be possible with passengers changing onto a bus (or a 153) at Tenby from Pembroke Dock, but at most it'd buy you one unit and (summer excepted) it's not a busy part of the network to benifit from a longer (LHCS) train.
Solving the short forms of 158s isn't as easy.
...
Alternatively, Porterbrook could hire locos and drag the 319s up and down the Valleys.
Cutting Holyhead-Birmingham back to Birmingham-Chester would save two units I believe; if you're bringing in locos anyway the Chester-Holyhead leg could then be worked by a rake of mark 2s (I'm assuming run-round is possible at Chester given the multiple through platforms). You could even do Holyhead-Chester-Crewe-Stafford-Bescot Stadium-Soho-BHM-Aston-Bescot Stadium-Stafford-Crewe-Chester-Holyhead avoiding the need to run-round anywhere except Holyhead and reducing the Birmingham-Holyhead journey time as a bonus. It might have to use the 'slow' lines on the WCML and it probably couldn't call at Wolverhampton due to unavailability of paths through that station (I'm not suggesting it call at Bescot and Aston, just listed them to explain the routing).