I will be visiting UK in September 2023 and have broadly completed an itinerary with hotels booked, as coming from a distant land it's not 1993, so one can't just turn up at most stations and expect to find a reasonably priced hotel with vacancies.
However plans can often be slightly tweaked.
Apart from the loco-hauled Chester-Holyhead TfW trains that I've decided not to travel on as I've done the line years ago and didn't find it overly interesting, are there any trains/railcar classes that one ought consider targeting?
Rollingstock that may be withdrawn within the next couple of years is a possible target. Is GWR's 'Castle Class' (not the steam locos of the same name) a small example?
What about those loco-hauled trains operating between London and the north?
For each such class, on what routes do they typically operate?
Class 43 - Edinburgh/Glasgow - Aberdeen/Inverness and Cardiff - Taunton/Plymouth/Penzance (plus one single diagram on Edinburgh or Leeds - Plymouth which will be withdrawn in October) is scheduled to slowly be wound down, but ScotRail examples are likely to last the rest of the decade as the replacements aren’t due for a long while
Class 68 - London Marylebone to Birmingham/Stourbridge should be withdrawn by Chiltern in 2024 and the only other operator of them (TransPennine) only uses them for a skeleton service, predominantly York Scarborough, and a decision will soon be made about their future since TPE is to be nationalised
Class 91 - London Kings Cross to Leeds/Bradford FS/Skipton/York - these are very old for mainline express trains and with the current trend in budget cuts bound to be withdrawn in favour of an Azuma only fleet at LNER
Class 139 - Stourbridge shuttle, near Birmingham - probably the most unique train ever operated in the UK - not doomed yet but apparently getting knackered and allegedly talks of replacements aren’t far off
Class 318/320/334 - Glasgow suburban services (334 also operates stopping services to Edinburgh) not immediately threatened but planned to be replaced by 2027.
Class 455 - London Waterloo to Hampton Court/Dorking/Guildford/Woking/Chessington currently remains in service in a similar situation to that of the NSW V Sets over here in Australia. As soon as the much delayed new sets finally enter service, they’ll be gone.
Class 458/5 - London Waterloo to Reading/Windsor/Weybridge - in their current unique formations of 458/0 with a random Class 460 carriage shoved in there, plus the few converted entirely from 460s, will be gone as soon as the much delayed 701s enter full service. Most of the former 458/0 carriages will be retained and overhauled for mainline use.
Class 465/466 - South East London and former Kent Greater London commuter services - a tender is being drawn for the replacement of these trains, an entire subclass of which (465/2) has been stood down already, so while these have a bit longer than the others, again I don’t know how long it’d be until you return from Australia again so perhaps one to consider.
Class 507/508 - Liverpool to Southport/Hunts Cross/New Brighton/West Kirby/Chester - I believe these will be the oldest EMUs in passenger service and have already been partially replaced by 777s so don’t have long left at all. There shouldn’t be any on Kirby/Ormskirk services in September.
Class 769 - Southport to Manchester Oxford Road/Stalybridge - with the budget cuts and these being notoriously unreliable, I’d get a ride in quick if you want one as I don’t see these lasting more than five years at an absolute max. Could say the same for TfW’s 230s tbh.
Class 994 - currently ALL Tyne & Wear Metro services - are to be replaced with new stock which this month begun testing on the network
DLR B9x stock - the 90s DLR trains that work the bulk of DLR services will be replaced during 2024 with new B23 stock that have begun testing on the network
Glasgow Subway stock will also be replaced in 2024 or 2025