SWR DMU issues

[adc82140]

A very unpleasant journey today on a 159 with no functioning aircon. The other unit in the consist was the same. The fact is the ventilation systems are 35 years old, I can't think of any other application where aircon would be expected to soldier on this long.

As there is no replacement for the 159s in the pipeline, something will have to be done if we continue to get summers like this.

Also on the same train, an engine had to be isolated. Fortunately it was on the unit that gets detached at Salisbury. They really are struggling.

 

[43096]

A very unpleasant journey today on a 159 with no functioning aircon. The other unit in the consist was the same. The fact is the ventilation systems are 35 years old, I can't think of any other application where aircon would be expected to soldier on this long.

The ventilation system is not 35 years old. The 159s (along with many 158 fleets) were fitted with new Liebherr aircon systems several years ago.

 

[RPI]

Indeed. Likely to be implemented in the first week of August according to the most recent All-Staff Call with the senior leadership team.

The journey time to Exeter will be slightly shorter than during the last SMD timetable.

SWR should just name it their "Summer timetable".

The problem with SWR is that they really don't give a flying fig about anything west of Salisbury.

I'd actually go as far as to say they don't give a flying fig about anything west of Basingstoke!

 

[adc82140]

SWR should just name it their "Summer timetable".

The problem with SWR is that they really don't give a flying fig about anything west of Salisbury.

I'd actually go as far as to say they don't give a flying fig about anything west of Basingstoke!

I'd agree with you there. I don't often travel to London, but it's two trips in two weeks for me. This week, aside from the aforementioned aircon issues, in the Londonbound direction from Salisbury on the journey in, we got terminated at Basingstoke, with the onward connection to London full & standing (fortunately I was heading for Reading).

Next week I'm taking the car.

 

[s491]

The ventilation system is not 35 years old. The 159s (along with many 158 fleets) were fitted with new Liebherr aircon systems several years ago.

Quite. The Liebherr system was fitted circa 2005 on the 159's. As an aside, several HST's used - still use - equipment that goes back 50 years on the Mk3 a/c and that still works fine....... Its called maintenance.

 

[Snow1964]

Not just SWR that has falling apart trains in South West
The GWR DMU fleet seems to be dying

The train being used for the Par to Newquay service has broken down, and a spare is not currently available.

The train operating between Swindon and Westbury via Melksham has failed and there is no spare train available to replace it

-The train that runs between Exeter St Davids and Okehampton has broken down.

Rather feels like a DMU crisis, breaking down, no serviceable spares, are they simply be worked unrealistically hard, beyond point where they can repair them fast enough

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[JohnofWessex]

I have advance tickets from Frome via SWR 07something to Waterloo return at 1630 on the direst service on the Friday when Sarah Siddons is running

What happens of the timetable is adjusted?

 

[Snow1964]

I have advance tickets from Frome via SWR 07something to Waterloo return at 1630 on the direst service on the Friday when Sarah Siddons is running

What happens of the timetable is adjusted?

If the train where you have an advance goes, or is changed, can use trains hour before or after, sometimes 2 hours. If connecting to another train then staff tend to be more flexible on enforcement because itinerary might no longer be followed without the time flex.

Reservations usually need to be changed manually, unless same train is basically tweaked and still around same time.

 

[JohnofWessex]

If the train where you have an advance goes, or is changed, can use trains hour before or after, sometimes 2 hours. If connecting to another train then staff tend to be more flexible on enforcement because itinerary might no longer be followed without the time flex.

Reservations usually need to be changed manually, unless same train is basically tweaked and still around same time.

Presumably though it would not include GWR services?

 

[Harpo]

This week, aside from the aforementioned aircon issues, in the Londonbound direction from Salisbury on the journey in, we got terminated at Basingstoke

Services from Salisbury & Exeter terminated at Basingstoke for most of the day on Friday 10/7. Be interesting to know if that was about heat (on a 32c day) or other general shortages.

 

[Newbury]

Services from Salisbury & Exeter terminated at Basingstoke for most of the day on Friday 10/7. Be interesting to know if that was about heat (on a 32c day) or other general shortages.

Supposedly heat related to avoid propagating delays through, supposed to happen again on Monday.
Very poorly communicated and organised, with some trains still showing as running through to London and last minute platform changes at Basingstoke only announced as the London-bound train was pulling in resulting in large numbers of people running for the subway.
Trains also weren’t often held for delays when coming from London, even in the evening when they drop down to 1tph

 

[TastyMaltesers]

Not just SWR that has falling apart trains in South West
The GWR DMU fleet seems to be dying
Rather feels like a DMU crisis, breaking down, no serviceable spares, are they simply be worked unrealistically hard, beyond point where they can repair them fast enough

I think ultimately the root cause is nobody wanting to commit to building DMUs after the Turbostars. Now throughout the country the fleets on non-electrified lines are increasingly old with nothing coming in to supplement them.

 

[BurningFeetMan]

Just to assist a little with understanding the issue;

Once the roof space gets too hot the air con has safety systems built in to prevent it running as it may have a fault. There are mods being trialled to attempt to negate this issue but they take time to test and prove before being rolled out.

Unfortunately, once the air con gives up then typically it cannot be fixed until the evening when temperatures have cooled enough.

Non working air con is considered a safety issue for passengers and staff (the small cab gets very hot, very fast).

Canceling or short forming trains is very frustrating for staff and of course passengers, please don't think this happens lightly.

 

[Lieut_green]

Presumably though it would not include GWR services?

Last year I had the situation happen to me with an exeter-southampton ticket, the initial change limited us to swr only but if there were cancellations we ended up being able to use gwr without issue via westbury

 

[brad465]

Supposedly heat related to avoid propagating delays through, supposed to happen again on Monday.
Very poorly communicated and organised, with some trains still showing as running through to London and last minute platform changes at Basingstoke only announced as the London-bound train was pulling in resulting in large numbers of people running for the subway.
Trains also weren’t often held for delays when coming from London, even in the evening when they drop down to 1tph

This may also have contributed to a rare 9-car going all the way to Exeter yesterday:

https://www.realtimetrains.co.uk/service/gb-nr:L79417/2026-07-13/detailed#allox_id=0

 

[RPI]

This may also have contributed to a rare 9-car going all the way to Exeter yesterday:

https://www.realtimetrains.co.uk/service/gb-nr:L79417/2026-07-13/detailed#allox_id=0

Usually the rear three would be locked out between Salisbury and Exeter if a 9 car

 

[sharpener]

However it isn’t some marketing BS made up to appease the accountants but a process introduced by Toyota, along with the Kanban principles, during their large upscale in the late 60s early 70s when small Japanese cars became more economical to the outside world than big American gas guzzlers.

It's good in a manufacturing environment as the suppliers have long-term call-off contracts and are incentivised to bring the stock to the shop floor or the gate in the wire (or rather are penalised if they don't).

It's no good in a maintenance environment bc even if the suppliers can fulfil in 24 hours the unit is out of service until the parts can then be fitted. You need them on a shelf in the same physical facility or at most 1 hr's drive away.

You can 3-d print metal items too, but it’s rather more expensive so not seen in the hobbyist market like the plastic ones.
But I suspect not economically enough for the rail industry to bother with.

Yes you can provided you have the drawings. With machinery of this age a lot of suppliers will have gone out of business, even those that haven't may not have usable drawings they can find. Scanning a worn or broken part is quite error prone.

Simple example: old Morphy Richards breadmaker drive belt apparently failed yesterday. Google AI said the correct one for that model no. had 175 or 179 teeth. Various online suppliers looked plausible.

When I took the bottom plate off it was a poly-V belt not toothed. Fortunately it had just come off and needed re-fitting, don't know how long that "repair" will last though.

Another example: ordered replacement spring for Felco pruners a week ago. Supplier sent wrong tracking number and DPD have THREE TIMES tried to deliver it to the wrong house with a totally different name at the other end of the village.

Fortunately neither is mission critical. But I do keep spares in the garage for all consumable parts for the rainwater treatment plant. The irony is that the 5000 litre tank level is now down to the first warning sensor, we need rain!

 

[swrcommguard]

Usually the rear three would be locked out between Salisbury and Exeter if a 9 car

Indeed only Salisbury, EXC and EXD have sufficient platform length for a 9-car on that line.

Usually this occurs only when there's an unplanned stock movement.

 

[pokemonsuper9]

This may also have contributed to a rare 9-car going all the way to Exeter yesterday:

https://www.realtimetrains.co.uk/service/gb-nr:L79417/2026-07-13/detailed#allox_id=0

It also happened last Thursday with 159012 + 159017 + 159020, the rear three were locked out but engine running (is the only SDO they have Unit Deselect for 6 to 3?)

https://www.realtimetrains.co.uk/service/gb-nr:L79417/2026-07-09/detailed#allox_id=0

 

[RPI]

Indeed only Salisbury, EXC and EXD have sufficient platform length for a 9-car on that line.

Usually this occurs only when there's an unplanned stock movement.

Out of interest, can the SDO not open 6 cars of a 9 car?

 

[Kite159]

Out of interest, can the SDO not open 6 cars of a 9 car?

SDO can do 6 coaches out of 9 (does it at Clapham Junction heading to London), however for some of the stations (Honiton for example) being at the rear of the train isn't ideal as you can't see the front due to the curve.

Having a 9 coach service to Exeter would mean the guard will be pretty much tied to the rear coach (moving forward for coach 3 for Tisbury/Feniton/Whimple) which means revenue won't be done

 

[RPI]

SDO can do 6 coaches out of 9 (does it at Clapham Junction heading to London), however for some of the stations (Honiton for example) being at the rear of the train isn't ideal as you can't see the front due to the curve.

Having a 9 coach service to Exeter would mean the guard will be pretty much tied to the rear coach (moving forward for coach 3 for Tisbury/Feniton/Whimple) which means revenue won't be done

Thanks for the explanation, that makes sense now.

Having travelled the route most days for ten years I can safely say revenue isn't even done on an empty 3 car most of the time.

I've only had my ticket checked 6 times going into Exeter in the past 10 months, twice by Revenue Protection and the other four times by the same Salisbury guard (who incidentally knows I have a valid pass and we generally have a chat).

Coming back from Exeter I've had one ticket check in that same time and that was by the tracsis DfT ticket survey people , however, we digress!

 

[swrcommguard]

Out of interest, can the SDO not open 6 cars of a 9 car?

Yes it can but due to the curvature on some platforms it's not safe to operate the doors from there as you can't see the whole train.

ETA: I see this has already been answered by a colleague.

 

[Snow1964]

Lord Hendy gave a Parliamentary answer on future of SWR 158, 159 this week

15 July 2026
The Class 158 and Class 159 diesel trains used on services between London Waterloo and Exeter are expected to be replaced as part of longer-term plans to modernise the rail fleet. South Western Railway, working with the Department for Transport, is developing proposals for their replacement; however, no specific timetable for replacement has yet been confirmed. In the meantime, these fleets are undergoing a phased refurbishment programme to improve reliability and passenger experience, including upgraded interiors, improved passenger information systems and the introduction of at-seat power. This ensures the trains remain fit for service while longer-term decisions are taken.
The Government is also developing a long-term rolling stock and infrastructure strategy, to be published later this year, which will set out Great British Railways’ future rolling stock requirements, including the approach to replacing older diesel trains.

https://questions-statements.parliament.uk/written-questions/detail/2026-07-06/HL1695

Not very good, eventually will be replaced, but no timescale yet
Still developing proposals - code for haven't got beyond ideas stage

Isn't it bit double talk to use term 'remain fit for service' when some aren't working and not fit for service.

 

[Harpo]

The biggest eye opener from Hendy’s statement is this:

The Government is also developing a long-term rolling stock and infrastructure strategy, to be published later this year, which will set out Great British Railways’ future rolling stock requirements, including the approach to replacing older diesel trains.

All hopes of GBR having future control over a national fleet plan died right there.

 

[Snow1964]

The biggest eye opener from Hendy’s statement is this:

All hopes of GBR having future control over a national fleet plan died right there.

In DfT jargon it is LTRS

Which it explains is a 30 year Long Term Rail Strategy which includes outline plan for new rolling stock needed over a rolling 20 year forward period.

Although having a set of framework deals covering standardised stock over few years, rather than lots of small non-standard cannot only be used on one route stock seems sensible to me, but only if they make it universal and quality, not built to lowest spec possible