I think 2030 is very optimistic for the 158s at this particular moment in time, to be honest.
2030 is roughly a 40-year life for them. By way of comparison TfW is the only current operator of class 150s with plans to replace them and they will be over 35 years old by that point - most other 150s will easily see 40 years in service. The 158s are of aluminium construction rather than the steel of the class 150s so if anything 158s should last longer.
With all due respect, you're typing this presumably from your own home - certainly by your own admission you've not been on a train for a year. The people telling you these units are knackered are the ones working on them day in day out. I'd like to think we're slightly better informed. You can give them as long as you want - but it doesn't change the facts.
The only other operator of 158s who had plans to replace them was EMR and it is now unclear whether they will go through with that. If the 158s are as knackered as you say (and, as you say, you know that better than me) then why are other TOCs keeping them and, more-importantly, why are there no plans to replace many of the even-older 150s?
Bi-modes are a funny thing. Even 10 years ago, they were the target of the naysayers - too heavy, won't work, etc etc etc. Then the 80x has come along and become (whatever you might think of the seats) a phenomenal success and proven the naysayers wrong (as usual), most notably transforming Paddington from a cloud of diesel fug and stink of human excrement to a much more pleasant place.
Bi-modes are still too heavy; but there's a big difference between the Cambrian (where there's no realistic prospect of electrfication, but bi-modes would support a case for wires between Wolverhampton and Shrewsbury) and intercity services (which should be electrified throughout).
To be honest (and I'm hoping this can be a rare thing we actually agree on!) I think the idiocy lies with the British government in not investing in electrification. There shouldn't be a debate over bimodes because there should be enough electrified track to make it moot.
As noted above, it's not moot because the Cambrian Coast won't be electrified in any likely scenario - although I do agree that the idiocy lies (predominately) with the British government for failing to electrify. The rail industry doesn't help itself by building new DMUs which damages the business case for electrfication.
Whilst the 170s are well-known for being a bit sluggish off the mark, and hence not best-suited to stopping services, it should perhaps be noted that a good number of them were never originally ordered for such purposes even if they do so now. Some of the early operators of Turbostars were Midland Mainline and Hull Trains, which used them on limited stop regional/intercity services. In fact if you consider the other early operators (Central Trains/Anglia Railways/SWT), they were predominantly used on regional services, which is where the class is arguably most at home, and not on stopping services on the Harrogate or Robin Hood lines for example.
Agreed they weren't built for stopping services, but the wide doors at thirds are optimal for stopping services and not for the regional express work they were ordered to do.
Stakeholders on the Cambrian were quite specific about keeping the ability to walk through between units, as services can be quite crowded at the Brimingham end. Gangways let you grab a seat wherever one's available, and swap units if needed whenever you like, rather than run between them while its at a station. That wisdom seems to have been applied to the other splitting services too.
Aye; I think TOCs should avoid portion working if their stock doesn't have unit end gangways for precisely this reason. If you have to get out of one unit and run to another, surely that's little different from having to change train so you might as well have a timetabled connection. At least passengers will expect to have to get off then. The provision of unit end gangways is something that TfW got right with the 197s.
We've had this door argument over and over - and those of us who work these routes keep telling you that the wider doors really are a good thing. We're not imagining this - we've seen the queues on the platforms trying to board 158s and 175s with our own eyes!
I've seen queues on platforms too, I just don't think that is as big a problem as some of the other things. I'd rather have a queue to board and get a comfortable table seat with a clear view out of the window that have to stand in the cavernous vestibule of a unit with wide doors. On a metro service the dwell times have to be prioritised - on a regional express I think it's wrong to prioritise dwell times. Yes dwell times would be less with a 197 than a 158 or 175 but the trade-of between passenger comfort and dwell times is not satisfactory to me.
Electrification isn't going ahead. Get used to it. In 10 years time we'd just be even more desperate for more units, only now they'd cost a lot more.
If electrification isn't going ahead, then it's probably symptomatic of a continued lack of action on decarbonisation in general. In that case, in 10 years time we could have a lot more to worry about that just needing more units. I'm not sure if this link will work for you, but it suggests
much of the line between Dovey Junction and Borth is projected to be below the tideline by 2030 due to sea-level rise.
Its interesting how upset some on this forum are by the 197s coming to replace old trains, especially considering that the ex-ATW fleet is overall pretty ancient and tired out.
People are treating minor problems like they mean the cancellation of the order.
If they were capable of electric operation the other issues wouldn't mean cancellation of the order - I would simply argue that they should be deployed elsewhere (to create a Swansea metro and, if any are left over after that, replace 150s elsewhere). But their door configuration renders them unsuitable for long-distance work in my view and their inability to operate off OHLE renders them unsuitable for the work they would otherwise be ideal for.