How long will the Class 158 & 159 soldier on for?

[brad465]

There is no reason not to use BEMUs for lines with a top speed of 85 or 110 or any other top speed.

New diesel units should not be considered. The current cheap railway diesel will not be available forever. New 3rd rail doesn't strike me as a good idea either.

For Waterloo-Exeter services, the solution (in my view) is to install OHLE around Exeter, and use this combined with the existing 3rd rail to charge batteries for the remaining section. The OHLE around Exeter can also be used by the existing 80x services and to charge BEMUs used on the other lines from Exeter, giving more benefit for the infrastructure investment.

I'd add another such OHLE island through Salisbury, which both ensures a mid-journey top-up for Waterloo-Exeter trains and can feed BEMUs on the Cardiff-Portsmouth route as well.

 

[RealTrains07]

SWR should have done the 158s and 159s refurbishment years ago, whats the point of doing it now when the both fleets realistically will be going in the next 5 - 10 years.

 

[greyman42]

SWR should have done the 158s and 159s refurbishment years ago, whats the point of doing it now when the both fleets realistically will be going in the next 5 - 10 years.

Well if it's 10 years then it's worth doing.

 

[Snow1964]

Well if it's 10 years then it's worth doing.

Thats only partly true

If start the refurb and find extra work such as corrosion repairs, then it changes the equation of repair or replace.

Take as an example, if look at it, and think only got 2-4 years before major work needed. Then think what happens if actually do major work eg replace corroded sections or have to buy new engines because current ones won't last another 10 years. But also realise repaired lifespan might only be about 7-8 years (by time actual do the train), so might be poor value spending a fortune to give only few extra years use.

And thats if it is actually possible to do corrosion repairs on a part steel, part aluminium train at an economic price, and retain structural integrity. If it becomes so complicated or specialist task doing it, and also doing a refurb, then might be say third of cost of a new train.

In blunt terms it is cost of corrosion work, buying parts for engines to keep them running for 7-10 years, and refurbishing for another 7-10 years usage versus not doing the work and expediting replacements.

Although I am not familiar with proposed refurb, I have heard stories that one has been taken for appraisal and work needed has turned out to be far more extensive (and presumably expensive) than expected. So much extra needs doing to extend life, that work has been halted as uneconomic. Maybe someone else can advise if a unit is actually on hold instead of refurb progressing.

 

[Tetragon213]

SWR should have done the 158s and 159s refurbishment years ago, whats the point of doing it now when the both fleets realistically will be going in the next 5 - 10 years.

Strangely, I think the existing interior design is actually just fine on the 159s. While yes, the legroom is a smidge lacking, the seats are still extremely comfortable (far more comfortable than the torture racks provided on modern units), and the number of luggage racks are in keeping with the amount of luggage that gets stored on board.

It's actually quite extraordinary how well the interiors are holding up, even on the oldest SWT ones, after all this time.

If the mechanics were better looked after, I could see these things going on for as long as the HSTs.

 

[Snow1964]

SWR have issued a tender for 3 years, September 2026 - September 2029 to provide spares, including engines and bogies for 158 & 159, value upto £70m

1 buyer​

• South Western Railway London

Description​

Provision of Spare parts and train engines for trains (SMA Bogies - Class 158/159)

CPV Codes​

• 34300000 - Parts and accessories for vehicles and their engines
• 34600000 - Railway and tramway locomotives and rolling stock and associated parts

Indicators​

• Renewals are available.

https://bidstats.uk/tenders/2026/W22/871235892

If they are considering having to spend nearly £1m per vehicle for parts in just 3 years, then have to wonder about the economics of not replacing them at current time. At that rate will be spending upto £4m per vehicle over 13 years.

£4m per vehicle is getting close to a new vehicle cost, which would have a design life of nearer 35-45 years, so 3 times as long.

So I do wonder about the whole life equivalent cost of continuing to patch up its old diesel fleet that were built 33-37 years ago, rather than replacing them before too many parts wear out completely.

 

[swrcommguard]

Are they? Reliability is not what it once was but they’re hardly 180s. The onboard environment of a Northern 150 is totally different to a 159.

The problem is a reliance on ****ty reconditioned engines that fail all too regularly and a lack of spare parts - some components now have to be hand made.

There are lengthy periods when up to a third of the West of England fleet is up on blocks. Just look at the number of short formations over the last few weeks - 18 carriages down on Mobday and 13 on Tuesday.

So while I am not criticising these units historic reliability, unfortunately they can no longer be relied on.

 

[absolutelymilk]

SWR have issued a tender for 3 years, September 2026 - September 2029 to provide spares, including engines and bogies for 158 & 159, value upto £70m

https://bidstats.uk/tenders/2026/W22/871235892

If they are considering having to spend nearly £1m per vehicle for parts in just 3 years, then have to wonder about the economics of not replacing them at current time. At that rate will be spending upto £4m per vehicle over 13 years.

£4m per vehicle is getting close to a new vehicle cost, which would have a design life of nearer 35-45 years, so 3 times as long.

So I do wonder about the whole life equivalent cost of continuing to patch up its old diesel fleet that were built 33-37 years ago, rather than replacing them before too many parts wear out completely.

I read it as the tender value being in the category of between £0 and £70m, not that the value was £70m!

 

[yorksrob]

The third rail 'islands' plan has bitten the dust. The national grid also kyboshed the plan when they were approached by NR.

The solution will have to be more diesels or a bi-mode that can use the 3rd rail between Waterloo and Worting Junction and then switch to diesel.

If diesel only, it's possible that they will stop going all the way to Waterloo and may terminate/turn at Woking (due to London clean air legislation).

I have heard talk of plans to change the xx.47 Salisbury to Waterloo stoppers to Yeovil to Reading services (probably from Dec 2027 or poss May 2028)

Nearly all Salisbury crew now sign Basingstoke to Reading and Yeovil depot will be learning it, too.

That all sounds very unsatisfactory. Through services to London need to be maintained somehow.

 

[Tetragon213]

A brief look at an old document from TfW's order of units...


Looking purely at the Class 231 order, it looks to be approx £7.5mil per unit. Let's extrapolate that to 38 units (8 Class 158s + 29 Class 159s in their current fleet, plus 1 that was written off during Salisbury Tunnel Jn), and you're looking at about £284 million. I think there should be some serious consideration of new Stadler FLIRTs for the WoEML.

Strictly theoretically, if you took the Class 756 order, transferred across the approx. £2mil from Sim/Mock up prices to the 756 cost, then divided that by the number of units (24), then multiply that across to 38 units, and finally multiply by 1.073 (to account for the 7.3% inflationary rise between 2023 and now), you get about £340 million. Surely it's not impossible to install a DC-AC invertor and a step up transformer from 750 to 25k? (edit due to maths error)

 

[norbitonflyer]

A brief look at an old document from TfW's order of units...

Surely it's not impossible to install a DC-AC invertor and a step up transformer from 750 to 25k? (edit due to maths error)

Why would you need to do that? As i understand it any unit taking an AC supply - even one using AC motors suich as a FLIRT - has to rectify it to DC to remove the 50Hz carrier before generating the variable frequency AC needed for traction.

So why convert a DC supply from the live rail to AC, only to convert it straight back to DC again?

 

[Zomboid]

So why convert a DC supply from the live rail to AC, only to convert it straight back to DC again

And then invert it again for the 3 phase motors

 

[Tetragon213]

Why would you need to do that? As i understand it any unit taking an AC supply - even one using AC motors suich as a FLIRT - has to rectify it to DC to remove the 50Hz carrier before generating the variable frequency AC needed for traction.

So why convert a DC supply from the live rail to AC, only to convert it straight back to DC again?

Every day's a school day! Never knew the current was converted into DC and then back into AC!

Regardless, that should mean that converting a Class 756 to run on 3rd Rail actually a bit easier potentially. For £350 million ish, that's a decent way to a) get some new rolling that that is actually quite liked, and b) take advantage of the existing 3rd rail supply to Worting Junction.

Imo they'd be best off electrifying with batteries down to Exeter via Salisbury. You get lower capital costs involved than building OLE/3rd rail, the whining NIMBY brigade of Salisbury won't get their proverbial underpants in a twist, and you can still keep the diesels on board for redundancy. Hopefully, in this theoretical world where they do this, they can also look into re-doubling the line to Exeter, as I do think there's untapped potential for getting traffic off the congested A303 via the WoEML.

 

[D365]

Regardless, that should mean that converting a Class 756 to run on 3rd Rail actually a bit easier potentially. For £350 million ish, that's a decent way to a) get some new rolling that that is actually quite liked, and b) take advantage of the existing 3rd rail supply to Worting Junction.

Do you mean converting the existing TfW units to add third rail pickup - and presumably moving them on to SWR - or new build?

 

[Tetragon213]

Do you mean converting the existing TfW units to add third rail pickup - and presumably moving them on to SWR - or new build?

New build, I was thinking. A fleet of Class 756 units with the pantograph and 25kV equipment replaced with the equipment required for compatibility with Third Rail DC and maybe battery chargers west of Worting Junction.

 

[Clarence Yard]

A brief look at an old document from TfW's order of units...

View attachment 204948
Looking purely at the Class 231 order, it looks to be approx £7.5mil per unit. Let's extrapolate that to 38 units (8 Class 158s + 29 Class 159s in their current fleet, plus 1 that was written off during Salisbury Tunnel Jn), and you're looking at about £284 million. I think there should be some serious consideration of new Stadler FLIRTs for the WoEML.

Strictly theoretically, if you took the Class 756 order, transferred across the approx. £2mil from Sim/Mock up prices to the 756 cost, then divided that by the number of units (24), then multiply that across to 38 units, and finally multiply by 1.073 (to account for the 7.3% inflationary rise between 2023 and now), you get about £340 million. Surely it's not impossible to install a DC-AC invertor and a step up transformer from 750 to 25k? (edit due to maths error)

The TfW numbers don’t translate because they are just the purchase price of the initial spares, not the annual cost of consumable spares nor the annual cost of repairable items.

 

[REVUpminster]

Transport for Wales have a lot of 158s.

 

[Rich McLean]

Transport for Wales have a lot of 158s.

Likely to be off to the North East for Northern once released to boost capacity, and releasing 156s back to Newton Heath to boost capacity in the West.

 

[REVUpminster]

Likely to be off to the North East for Northern once released to boost capacity, and releasing 156s back to Newton Heath to boost capacity in the West.

Why go to Landore? Looking at it; it is only running as required so probably will not.

 

[HamworthyGoods]

Transport for Wales have a lot of 158s.

Which remain on lease to TfW for a number of years still.

 

[Goldfish62]

Which remain on lease to TfW for a number of years still.

What are they going to be used on once the 197s replace them all on existing services?

 

[TastyMaltesers]

What are they going to be used on once the 197s replace them all on existing services?

Scrap metal, perhaps? I've seen tale that the 158s have been vulnerable to corrosion (as SWR are finding out trying to refurbish their own fleet)...

 

[REVUpminster]

Scrap metal, perhaps? I've seen tale that the 158s have been vulnerable to corrosion (as SWR are finding out trying to refurbish their own fleet)...

Bristol will get the Exeter 158s when the 175s prove reliable. Bristol might want some TFWs 158s as well to strengthen services there. which badly need it.

 

[DS25]

Scrap metal, perhaps? I've seen tale that the 158s have been vulnerable to corrosion (as SWR are finding out trying to refurbish their own fleet)...

Northern or GWR, or TfW may want to keep them for a bit longer on a different route?

 

[Sporty60]

Corrosion and spare parts aside these are great for me on the Devon Metro and Exeter to Waterloo services.

 

[brad465]

If GWR, SWR and Northern all get their respective fleet order's approved before TfW's 158s go off-lease, at best I think they will be parts' donors to keep the other 158s going while the new fleets are in production. The exist of ETCS kit and the time taken to properly incorporate a cascaded fleet, even where existing classmates are already in use, will not make their introduction into service elsewhere worthwhile.

 

[The exile]

Why does the little voice inside my head say “until about 9 months before any of their replacements are ready “?!

 

[D365]

If GWR, SWR and Northern all get their respective fleet order's approved before TfW's 158s go off-lease, at best I think they will be parts' donors to keep the other 158s going while the new fleets are in production. The exist of ETCS kit and the time taken to properly incorporate a cascaded fleet, even where existing classmates are already in use, will not make their introduction into service elsewhere worthwhile.

Unless memory fails me, Phase 1 of Northern's Class 780 / 781 will be replacing Class 150, Class 155, Class 156 and Class 769 only. Phase 2 will be needed to see off the Class 158s.

 

[RUK]

As far as I am aware, new replacement rolling stock procurement has started for Northern, GWR, Chiltern, and TfW to replace their Sprinters, Super Sprinters, and Networker Turbos, but there are no current plans for EMR’s Class 158s, which are of a similar age, to be replaced. When do you think this will happen?

 

[dk1]

In a fairly recent magazine interview with EMRs MD it was mentioned sometime in the early 2030s for the 158s and why that fleet was only being refreshed rather than refurbished. He wouldn’t be drawn on whether their replacement would be new build or a cascade as obviously he has no idea.