Class 158 vs 159

[Lukespenceruk1]

sorry If this is a stupid question.

But I always wondered what’s the difference between them other then operators...

Is there a technical difference?

 

[mugam4]

First class and retention tanks.

And they're cleaned more than annually.

Edit: According to Wikipedia, 158s have 350hp engines to the 159's 400hp, except for 158863—158872 intended for now ATW (now spread across ScotRail, EMT, ATW and Northern)

 

[Kneedown]

sorry If this is a stupid question.

But I always wondered what’s the difference between them other then operators...

Is there a technical difference?

I can't really say for certain as we don't touch 159's, but i'm not aware of any technical differences. Certainly none that havn't been retrofitted to EMT/SWT 158's at least

 

[superkev]

I was always puzzled why the souped up 400hp 158's which where initially allocated to Cardiff for the marshes lines did not have a different class number like the 159's.
This, when the 158's where all 158's moved around when tp released it would have perhaps allowed swt to to have an all 400hp fleet or the benefits of the extra 50hp used on a dedicated route like the s and c.
Northern have just one 400hp (872) with two more recently received (870/1) from scotrail with the remainder expected soon.
K

 

[Spartacus]

I would say it's just the retention tanks as the ex-TPE 158s had first class too, which is rather bizarre as you'd think it would be the engine types, but there you go.

Incidentally, when SWT got it's hands on the TPE 158s and decided to convert them to 159s it was discovered that no drawing of the retention tanks existed/could be found and someone had to be tasked with the job of dismantling and reverse engineering one that had been in use for some years!

 

[dgl]

Also the auto coupler was originally wired differently to that on a standard 158 so that they could not be pinched by other bits of British Rail, thankfully now undone.

 

[InOban]

Then why is the Salisbury-based fleet of 159s so much more reliable than any fleet of 158s?

 

[gazthomas]

Then why is the Salisbury-based fleet of 159s so much more reliable than any fleet of 158s?

I’m sure the confined nature of operations, with the single maintenance base at Salisbury is probably a factor

 

[D365]

Also the auto coupler was originally wired differently to that on a standard 158 so that they could not be pinched by other bits of British Rail, thankfully now undone.

Never heard that about the 159s before - sounds like standard NSE policy for their Turbo-era diesels.

 

[edwin_m]

I'm pretty sure the 159s retained the Regional Railways coupler configuration, it was only the Turbos that had a different one (and the 168s built or modified to match them). If the 158s and 159s are incompatible then SWT must have modified its 158s to match the 159s, in which case it would make sense to call them all 159s.

 

[59CosG95]

I'm pretty sure the 159s retained the Regional Railways coupler configuration, it was only the Turbos that had a different one (and the 168s built or modified to match them). If the 158s and 159s are incompatible then SWT must have modified its 158s to match the 159s, in which case it would make sense to call them all 159s.

I think they must have modified them, but the 2-car 158s it picked up were renumbered into the 158/8 series (880-890) in order to differentiate them from the 3-car 159s they operate. It could alternatively be the case that the 159s were modified to match the 158s, as 158889 is now running happily around the East Midlands, and 1 member of the fleet is on rotational loan with GWR each day...

 

[hexagon789]

I would say it's just the retention tanks as the ex-TPE 158s had first class too

Originally only ScotRail's allocation of 158s had First Class, all other 158s were Standard Class only from new.

I believe the primary differences are the 159s were originally all 3-car, had retention toilets fitted (so only one Lavatory in the centre car instead of two), all had 400hp Cummins engines and all were fitted with improved First Class (2+1 as opposed to 2+2 in the ScotRail units.)

 

[Domh245]

The RSSB document on coupling configurations suggests that the 159s have the same electrical connectors as 158/156/155/153/150/144/143/142s, and that it is the 165/166s that have got slightly different configurations

 

[InOban]

I’m sure the confined nature of operations, with the single maintenance base at Salisbury is probably a factor

I'm sure that's a major factor. I've also been told that the base is staffed by ex-army engineers. But l have always wondered whether they have replaced original kit (door mechanisms, a/c etc) with higher quality stuff. The consequences of a failure on the approaches to Waterloo would be highly disruptive, and expensive.

 

[edwin_m]

I'm sure that's a major factor. I've also been told that the base is staffed by ex-army engineers. But l have always wondered whether they have replaced original kit (door mechanisms, a/c etc) with higher quality stuff. The consequences of a failure on the approaches to Waterloo would be highly disruptive, and expensive.

It probably also helps that the useage of the 158/159 fleet on SWR is "peaky" so there are spares at Salisbury during the day. Thus if there is a problem developing the unit in question can be swapped out next time it passes Salisbury and repaired before it becomes a full-blown failure. The other operators of the 158 are on regional routes where they don't have that sort of spares provision, and probably don't want to cancel a service unless the unit has actually failed.

 

[cjmillsnun]

Originally only ScotRail's allocation of 158s had First Class, all other 158s were Standard Class only from new.

I believe the primary differences are the 159s were originally all 3-car, had retention toilets fitted (so only one Lavatory in the centre car instead of two), all had 400hp Cummins engines and all were fitted with improved First Class (2+1 as opposed to 2+2 in the ScotRail units.)

They also have (as do SWR's 158s and 159/1s as it was retrofitted) The driver's end door lockout so that the driver can lock out the doors immediately behind their cab.

I believe SWR 158s and 159s have had the air con replaced with a more reliable system.

 

[cjmillsnun]

The RSSB document on coupling configurations suggests that the 159s have the same electrical connectors as 158/156/155/153/150/144/143/142s, and that it is the 165/166s that have got slightly different configurations

They do, but some suspect they originally didn't and have been returned to the original configuration once SWT gained 158s to use in the fleet.

 

[furnessvale]

Also the auto coupler was originally wired differently to that on a standard 158 so that they could not be pinched by other bits of British Rail, thankfully now undone.

And people tell me that renationalisation would be a good thing with the standardisation it would bring!

 

[D365]

And people tell me that renationalisation would be a good thing with the standardisation it would bring!

I don't see what minor and generally inconsequential modifications have to do with nationalised vs privatised rail.

 

[themiller]

From memory, the 159s were built as 158s then converted. Couplings and power controller settings are the main things that come to mind but it's so long ago that details are hazy! I also thought that the 159s were built wider than the 158s and Wikipedia shows this but is contradicted by Platform 5 who give identical widths.

 

[InOban]

It probably also helps that the useage of the 158/159 fleet on SWR is "peaky" so there are spares at Salisbury during the day. Thus if there is a problem developing the unit in question can be swapped out next time it passes Salisbury and repaired before it becomes a full-blown failure. The other operators of the 158 are on regional routes where they don't have that sort of spares provision, and probably don't want to cancel a service unless the unit has actually failed.

I've been told that also, and that such a swap out doesn't count as a failure in the national statistics. But do all these factors account for the difference in reliability?

 

[brel york]

158-159 are the same width

 

[Shaw S Hunter]

Then why is the Salisbury-based fleet of 159s so much more reliable than any fleet of 158s?

I’m sure the confined nature of operations, with the single maintenance base at Salisbury is probably a factor

The key is the diagramming. From memory something like 85-90% of diagrams either overnight at Salisbury or spend a decent chunk of time there during the day (between the peaks). This greatly assists the depot in identifying and rectifying minor issues before they develop into something more serious. Salisbury's geographic location on the route makes such diagramming fairly staightforward. All in stark contrast to say Northern DMU diagrams which can go 3 or 4 days without visiting an actual maintenance depot.

 

[dp21]

The key is the diagramming. From memory something like 85-90% of diagrams either overnight at Salisbury or spend a decent chunk of time there during the day (between the peaks). This greatly assists the depot in identifying and rectifying minor issues before they develop into something more serious. Salisbury's geographic location on the route makes such diagramming fairly staightforward. All in stark contrast to say Northern DMU diagrams which can go 3 or 4 days without visiting an actual maintenance depot.

I've been told that because so many 158/159 diagrams on SWR run in multiple they run with a high degree of redundancy and as such don't cause many delays.

 

[GW43125]

First class and retention tanks.

And they're cleaned more than annually.

Edit: According to Wikipedia, 158s have 350hp engines to the 159's 400hp, except for 158863—158872 intended for now ATW (now spread across ScotRail, EMT, ATW and Northern)

Only 159/0 are 400hp
159/1 are 350hp

159/0 were built as 158s but never ran as 158s
159/1 were also built as 158s but did run as 158s for a while. That’s why the carriage numbers don’t match up with the unit numbers!

 

[coppercapped]

Then why is the Salisbury-based fleet of 159s so much more reliable than any fleet of 158s?

Christian Roth.

(And all the other South Western Trains fleets compared to other operators).

 

[Kneedown]

I also thought that the 159s were built wider than the 158s and Wikipedia shows this but is contradicted by Platform 5 who give identical widths.

If a 158 was any wider it would out of gauge, hence why vinyl nameplates are used on EMT as opposed to proper cast ones.
Head of Fleet gave me this reason.

 

[delt1c]

dont remember what the mods were , but the 159'[s were built as 158's for RR but was realised before they entered service that they were not required. The completed units were taken to Rosyth were they were converted to 159. At the time it was said that the conversion made them incompatible with 158's. So the original 159's never ran in service as 158's

 

[hexagon789]

dont remember what the mods were , but the 159'[s were built as 158's for RR but was realised before they entered service that they were not required. The completed units were taken to Rosyth were they were converted to 159. At the time it was said that the conversion made them incompatible with 158's. So the original 159's never ran in service as 158's

I have heard it said that the 159/0s originally had an additional brake step. I've seen this written in a couple of forums and websites, but I've never seen any hard proof that this was ever the case. It seems strange that a sole, relatively small class would be given a non-standard version of the ubiquitous three-step brake. Personally, without any proof, I think it's unlikely but I'm curious as to how such an idea developed.

 

[delt1c]

they were modified before entering service so there must have been a difference to justify the cost of modification