when do you think the very last mark 3 based stock will run?

Given that a number of HSTs with Mk3 coaches will be snapped up by railtour companies once they're retired from frontline service, I expect them to be running for a very long time yet! If you mean in revenue service with a TOC, then I suspect the last ones will be in Scotland and the West Country, with the very last ones in Scotland, probably in the late 2020ies, maybe very early 2030ies.

I wouldn't object to 150s being around for a while, and you're right in that we're short on DMUs. However there have been rumours that the government and NR are considering backtracking on their "no DMUs" line as there is such a need. I still think the HSTs + Mk3s will be around the longest in service, and possibly HSTs + Mk4s, but I don't doubt that there will be some DMUs still working away day in day out in quiet corners of the network - the West Country brances, for example. As long as they're refitted to meet disability regs etc etc. I am quite the fan of DMUs, especially BR DMUs and will be sad when the last ones leave service.

As for electric Mk3 stock, I quite like the 317s. I suspect they will be moved off the Liverpool Street lines as electrification spreads (which much complaining from the recipients about receiving second hand stock etc etc), but I think they will have a long innings. Third-rail, there's the 455s - SWTs have had a lot of work over the years and will certainly be around for a while once they've had their traction equipment replaced. As much as I would like to see my 442s stay in service somewhere, I can't see where that will be, unless the DfT forces them back on SWT. While they should last longer than any HST Mk3 (based on the build date), I think we'll see them withdrawn in the next few years. Southern won't want to keep them as they're getting new trains and they're not fit for use on the GatEx. I'd like to see them back on Weymouth fasts (with their original interior, but that will never happen), with 444s supplementing them and being used on Portsmouth fasts, freeing up more 450s for slows and train lengthening.

I'll have to agree with you there, but if you are in need of diesel stock to operate services, and the HST power cars are available and so are the mk4s, then you could couple them together, but you would need to do some rewiring, as on the HST, the hotel electricity is generated in the power car (at 415V AC ISTR), and then sent along the train, whilst on 'conventional' LHCS, there is an alternator on each car that powers that coach. The easier option is to "chilternise" the HST mk3s by refurbishing and fitting power doors, which is what Abellio are doing for the new scotrail franchise.

The SWT 455s are intended to last until the start of XR2 services, as the new XR stock will be taking over the majority of the SWT metro routes through Wimbledon, complemented by the new class 707s for windsor side metro work, the 455s should then be able to be retired. The 456s, no longer having their 455 workmates might be retired around the same point, or may end up being sent off to SouthEastern, who seem to be desperately short of stock.

The southern 455s are starting to be wound down, with the new franchise seeing a decreased reliance on them. These might also be in contention for SouthEastern, but might equally be internally cascaded down to the East/West coastways to allow the cascading of 377s for strengthening mainline services, and the retirement of the 313s. Of course, the 455s would need to be retrofitted with toilets to keep the coast dwellers happy, but they would need to go through some life extension work (eg retractioning them, deep refurbishment, etc) before going down there.

There ought to be no issue with the slam doors as they have had central door locking fitted for many years now. The only problems occur when passengers un-used to them fail to close them afterwards!

There are far more pressing needs for withdrawal, Pacers would have the likes of TfL up in arms if they were running in London!

Not easily - the mark 3s used by EC and GW are HSTs which are essentially multiple units, whereas the mark 4s are hauled stock - although presumably they could be hauled by class 68s or the like. Designed with the capability for retrofitting tilt, the Mk 4s are more complicated and have narrower, less spacious, bodies. Frankly, the Mark 3 is a better vehicle than anything built since, and is also more adaptable.

Some HST's have been earmarked for new work on long distance non-electrified routes in Scotland.

Quite possibly: there may be a use for them and the mark 4s on cross country electrified routes - transpennine perhaps - but they are racehorses, not ideal for stopping services - or freight for that matter. They have already lasted longer than the Atlantics or the Deltics did on front line work: arguably the Pacifics as well given there were at least three generations of them in the forty years from 1922 to 1962.



All but one of the vehicles in the prototype HST of 1972 are still in service: two are in the measurement train, two in the Royal train, and the rest are still in normal passenger service. I think it quite possible that one or more of these might last another seven years



Longest or last? An important distinction given that the production run spanned fourteen years.

Now that most of the PEP based stock has replacements on order or at least contemplated, the bell may soon be tolling for the oldest Mk 3 emus - the 317s of 1981, but I can't see them going for a while yet. Nor is it likely that SWT's 455s will be going anywhere soon - they are currently undergoing a re-motoring which should see them through until Crossrail 2 comes along (in 2030 or so) Although officially introduced in 1982, the fleet incorporates two ex-class 210 cars of 1981, (and 43 ex-class 508 cars of 1978, although these are of course not Mark 3s!)

Dates of introduction of the other types:
150 (1984) - although the Pacers are ahead of them in the queue, increasing electrification and the greater strains put on a diesel-powered vehicle suggest these will not last as long as their electric cousins, unless the current difficulties in designing new emissions-compliant diesels persist.
318 (1986) - Scotland's rapidly expanding electric mileage needs all the electric units they can get hold of. I don't think replacement of even the PEP-based 314s is on the cards yet
319 (1987) - just starting a new life in the north west:
321 (1988) - a large fleet, which often means a long life
320 (1990) - probably their fate is tied up with the similar but older 318s with which they work interchangeably: I would guess replacement of the 314/318/320 fleet with one new type might be on the cards in the mid-to-long term (50 units in total)
322 (1990) - only five units, although really a subclass of 321. If more 321s go north to join them their future looks safer.
456 (1991) - their fate is really tied to the 455s - they do not make a usefully large fleet on their own (and see below). On their own they could only form six eight car trains, or (four ten-car and a single eight-car), and with six or eight redundant driving cabs in such a formation they would hardly be a good use of space. However, if some electrified country branches could be found where a three or four car unit would be a waste, there may still be a home for them - especially if they can be converted to ac. (Think of Chiltern's "Bubble Car" 1st generation dmu)
325 (1995) - little used to date: and with no seats or windows, much less to wear out. I think these could surprise us.


Can't see them being desired by SE - they are older than, and not compatible with, any of their existing stock, and being able to form, at most, four 12-car trains (with no less than ten redundant driving cabs wasting space) they would not be very useful. SE's stock shortages need resolving on a much shorter timescale than the 456s would become available - Crossrail 2 isn't going to happen until 2030 at the earliest.

That will increase the Scottish Mk 3 emu fleet to 57. I wonder if enough 317, 319, 321 or 322 units will be reduced to 3 cars to allow the elderly PEP cars in the 455s to be replaced?