What happened to all the 31's?

Steve Harris

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Alternative theory: it was during the great dessert crisis of the late 90s - the remaining fleet were put to work hauling emergency supplies from the Ambrosia factories, but it was soon found that they couldn't pull the skin off a rice pudding, so that marked the end of them.
Funny you should say that. I always knew 31's as "peddles" ie peddle power aka f*g useless. A 31/4 with 5 on was ok on Peterborough - Birmingham, but if you had 8 or 9 on, you may aswell get out and walk (as it was quicker)!

Getting back OT most 31's ended up in the "engineers/civils" sector on privatisation (dutch livery and the orange and yellow squares come to mind). Nearly always operated in pairs (because they needed to be to lugg rail and ballast etc around) and nearly all ended up being scrapped!

:lol: indeed

I was going to suggest there are a couple of them on New Street - Norwich trains that are still out in the fens somewhere.
To be fair, 31/4's with 5 on was ok to trundle along at the same speed as a dmu (ely - norwich used to be class 101's at 70mph) and would happily keep to time. No good sticking one on a Norwich - Liverpool St though. And certainly not the "European" !

I can remember the European calling at platform 3 at Ely with about 5 coaches hanging off the platform ! And no one ever opened a door and fell onto the ballast !! Hooray for 'elf n safety. Much needed in some parts of industry but by jolly it also means that generations younger than me have poorer common sense because of it.

Yes after rebuild with EE power units they were pretty reliable and were perfect for short engineers trains/ speedlink and some passenger trains. The ETH fitment in the 1970s made them very useful as well. They were under powered compared to a class 37 but no worse than any other type 2. They disappeared in the late 90s as they were over due overhauls coupled with the demise of some of the lightweight traffic they were used on.
With the aforementioned services above what 31/4's were primarily used on, the traffic didn't demise, as the services went over to "Sprinters".

In the case of Cambridge - Birmingham N S. the service went 31/4, Class 150, 156, 158 and finally 170.
 
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birchesgreen

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Having all wheels/axles powered would normally be a no-brainer but that would have necessitated them being an EE Type 3, otherwise known as a Class 37. It doesn’t make a lot of sense to us now but I suppose at the time there must have been a definite need for a less powerful locomotive.
Power output determines the type classification not the number of powered wheels. Early on in the locomotive's life British Railways experimented with various power outputs, even making one a type 4 though the Mirrlees engines were soon replaced by the EE units we now know and love.
 

Clarence Yard

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A Brush 2 was relatively slow off the mark compared to a Sulzer 2 but had more pulling ability. Once you got a load going, you could get it slowly up to speed and it would happily stay there. However, stopping a 31 with a large load could get a little interesting for the unwary.

In the KX Division we used them quite happily on smartly timed load 6 “block enter” suburban trains, the 8 coach Peterborough “Parly” workings and for shifting long & heavy ECS trains out from KX and over the Wood Green flyover from a standing start at Waterworks Washer.

I don’t think the WR and LMR ever really got on with them. Whilst they were an adequate replacement for a WR cl.22 on local and ECS work, trying to make them a Hymek replacement was a stretch too far. The LM missed their cl.25, which were more ideal for trip work and they seemed to have a certain amount of trouble keeping them “tight” - I and other ER men used to note the amount of off beat sounding locos that we used to see when we saw them as LM allocated locos. Maybe that was more down to stretching the duty cycles, I don’t know.

It really mystified us when the word got round that they couldn’t pull. That wasn’t what we experienced at all - they were more than adequate for the work we gave them, as long as you kept them in decent nick. ETH is always a factor but that really doesn’t account for the vastly different view of their abilities.

One thing was certain, however. Run them hard with No 1 end leading and they would boil. Finsbury Park (which at that time had the duties to prove it) was the test depot for the Rad Fan mod that would eventually help cure that issue but the internal aerodynamics of the class, after the EE engine was fitted, left something to be desired.

The reason they stuck around is that they were cheaper to look after than a Sulzer 2 and they effectively died out when either their duties did or surplus cl.37 locos became available.
 

DustyBin

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Power output determines the type classification not the number of powered wheels. Early on in the locomotive's life British Railways experimented with various power outputs, even making one a type 4 though the Mirrlees engines were soon replaced by the EE units we now know and love.

What I’m getting at is you can’t have six powered axles and only four traction motors though (sorry it’s maybe not clear). It would have been easy to make them a Type 3 using the same spec engine as the 37 (the intercooler being the main difference) but how would they have transferred this additional power to the rails? They’d have had to have used the same electrical equipment, traction motors etc. and become Co-Co in the process; basically a flat front 37.
 

birchesgreen

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What I’m getting at is you can’t have six powered axles and only four traction motors though (sorry it’s maybe not clear). It would have been easy to make them a Type 3 using the same spec engine as the 37 (the intercooler being the main difference) but how would they have transferred this additional power to the rails? They’d have had to have used the same electrical equipment, traction motors etc. and become Co-Co in the process; basically a flat front 37.
Probably wouldn't have all fitted, the Class 37s are a fair bit longer.
 

Western Lord

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What I’m getting at is you can’t have six powered axles and only four traction motors though (sorry it’s maybe not clear). It would have been easy to make them a Type 3 using the same spec engine as the 37 (the intercooler being the main difference) but how would they have transferred this additional power to the rails? They’d have had to have used the same electrical equipment, traction motors etc. and become Co-Co in the process; basically a flat front 37.
The engine power was limited so as not to exceed the capacity of the cooling group.
 

hexagon789

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I can see how monomotor bogies work, although I hadn’t really thought about them in the context of this discussion. It’s no different to having multiple powered axles on an HGV really. Two motors powering three axles could be done, I’m sure it would throw up problems though. Modern control systems could probably overcome them but we’re into “solution for a problem that doesn’t exist” territory I think!
It was about the only other way I could think of doing it but with more motors than usual with that system.

In regard to the 40s, 44s, 45s and 46s it’s a similar story; they were simply too heavy to get away with a Co-Co arrangement. If you look at their younger relatives (the 50s and 47s respectively) they were more powerful but lighter; again I think it can be put down to advances in technology. We now have Type 5 Bo-Bo locomotives to prove the point!
To prove the point -

HS4000 Kestrel - 3,775hp effective traction output from engine. Weight 133 tonnes

Class 68 - 3,805hp engine. Weight 85 tonnes.
 

matchmaker

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Power output determines the type classification not the number of powered wheels. Early on in the locomotive's life British Railways experimented with various power outputs, even making one a type 4 though the Mirrlees engines were soon replaced by the EE units we now know and love.
I understood that the electrical equipment was limited in its capacity, hence the EE engine fitted was the 12SVT, not the intercooled 12CSVT used in the 37s.
 

theblackwatch

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To be fair, 31/4's with 5 on was ok to trundle along at the same speed as a dmu (ely - norwich used to be class 101's at 70mph) and would happily keep to time. No good sticking one on a Norwich - Liverpool St though. And certainly not the "European" !
I have similar mixed memories of 31s. Doing them on South Yorkshire 'scratch and flash' tickets between Doncaster and Sheffield on load 4 Hull-Manchester services, they were ideal. I also have happy memories of 31s on load 4/5 in the North West on services around Liverpool/Manchester/Blackpool/Barrow, and even the Oldham loop, in the early 90s. But the days of coming back home to Yorkshire on a Cross Country service with a single 31/4 after a day spotting in Birmingham, probably load 8 or 9, we'd end up late! More the fault of the railway for using them on services they weren't suited for I'd say.
 

randyrippley

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A discussion of Class 31s always raises that they were underpowered. Yet the class was long-lived, with some surviving to carry Regional Railways livery. Why were they not withdrawn earlier? Were they particularly reliable?
They had EE engines = more reliable than Sulzers

Interesting thanks for the info. So really, was the design flawed? Driving all wheels should be a no-brainer, right?
..
And what about the 40s, 44, 45, 46s. Why did those gigantic engines have non-driving wheels?
the unpowered axles were on pony trucks attached to the powered bogies, acting as guides on curves
 

Richard Scott

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They had EE engines = more reliable than Sulzers
Think the Brush electrics were more reliable than the AEI ones on the 25s (doubt they were better than Crompton fitted 26s though) and even though 30tons heavier still had an extra 220hp installed and the extra axles meant they were still RA5 (mostly, think 31/4 may have been RA6?).
 

61653 HTAFC

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Funny that there's this thread asking what happened to the 31s, when I was always somewhat surprised that a handful of them lasted in passenger service longer than almost all other diesels of that era: there was the FNW service between St. Anne's & Greenbank; and Wessex Trains used them on the Bristol to Weymouth route. Wessex even had at least one repainted in a version of their house colours.
 

Irascible

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It was about the only other way I could think of doing it but with more motors than usual with that system.


To prove the point -

HS4000 Kestrel - 3,775hp effective traction output from engine. Weight 133 tonnes

Class 68 - 3,805hp engine. Weight 85 tonnes.
Might have been a bit lighter with a fast running engine rather than that Sulzer, although I don't know if there was one with that output around.
 

hexagon789

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Might have been a bit lighter with a fast running engine rather than that Sulzer, although I don't know if there was one with that output around.
I suppose a lot of it is improvements in engine technology, transmission and probably body design as well.
 

Irascible

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I suppose a lot of it is improvements in engine technology, transmission and probably body design as well.

That was very early days for things we take for granted now, like AC main alternators - iirc there was a practical limit of about 2700bhp into a DC gen before you got too much risk of flashovers. Brush had done a lot of theoretical work on AC transmission in the 60s, but it was all fairly new. Thyristors were developed in the 50s & Brush had actually done a build with AC traction motors in the 60s, but I guess they weren't confident enough to go the full way with Kestrel.
 

DustyBin

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I suppose a lot of it is improvements in engine technology, transmission and probably body design as well.

The point about body design is a good one, there was some “steam age” thinking applied when designing early diesels and I suspect chassis etc. were over engineered. There were certainly no lightweight materials, stressed skins etc. in those days!

That was very early days for things we take for granted now, like AC main alternators - iirc there was a practical limit of about 2700bhp into a DC gen before you got too much risk of flashovers. Brush had done a lot of theoretical work on AC transmission in the 60s, but it was all fairly new. Thyristors were developed in the 50s & Brush had actually done a build with AC traction motors in the 60s, but I guess they weren't confident enough to go the full way with Kestrel.

Very true, it’s easy to forget how much things have developed over recent decades.
 

Richard Scott

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That was very early days for things we take for granted now, like AC main alternators - iirc there was a practical limit of about 2700bhp into a DC gen before you got too much risk of flashovers. Brush had done a lot of theoretical work on AC transmission in the 60s, but it was all fairly new. Thyristors were developed in the 50s & Brush had actually done a build with AC traction motors in the 60s, but I guess they weren't confident enough to go the full way with Kestrel.
Think first diesel locos with AC motors were DSB ME1500s built in 1980s. Expect the control electronics weren't sufficiently developed at the time of Kestrel to allow a reliable AC drive.
 

randyrippley

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The point about body design is a good one, there was some “steam age” thinking applied when designing early diesels and I suspect chassis etc. were over engineered. There were certainly no lightweight materials, stressed skins etc. in those days!
Kestrel used a stressed-skin body based on those of the class 47
The class 47 body was an attempt to get away from the steam-age solebar bodies of the class 40 and Peaks
 
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70014IronDuke

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Alternative theory: it was during the great dessert crisis of the late 90s - the remaining fleet were put to work hauling emergency supplies from the Ambrosia factories, but it was soon found that they couldn't pull the skin off a rice pudding, so that marked the end of them.

Then there was that unofficial 1988 Cricklewood experiment to test two 31s as a novel rail-road traction combination, the idea being to put slow running freight on the down section of the M1 for a few miles to add capacity on the MML during the evening peak. It failed at the first roundabout, of course.
 

DustyBin

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Kestrel used a stressed-skin body based on those of the class 47
The class 47 body was an attempt to get away from the steam-age solebar bodies of the class 40 and Peaks

It was the 40s etc. that I had in mind when I referred to “steam age” more so than 47s and other 60s designs. I imagine much of Kestrel’s weight was in the engine and traction equipment.
 

Irascible

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Think first diesel locos with AC motors were DSB ME1500s built in 1980s. Expect the control electronics weren't sufficiently developed at the time of Kestrel to allow a reliable AC drive.
Brush Hawk ( rebuild of 10800 ) was AC all the way, but obviously experimental. AC drive with a fast diesel ( Maybach I think ), that was a very forward looking attempt.
 

30907

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Then there was that unofficial 1988 Cricklewood experiment to test two 31s as a novel rail-road traction combination, the idea being to put slow running freight on the down section of the M1 for a few miles to add capacity on the MML during the evening peak. It failed at the first roundabout, of course.
:lol::lol:
 

gg1

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25s were a lot lighter (just 73 tons), so unsurprising that 31s were more sluggish with about 30 tons more weight to lug round.
Why were the 31s so much heavier, not just compared to 25s but to the other DE type 2 classes too?
 

D5645

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Why were the 31s so much heavier, not just compared to 25s but to the other DE type 2 classes too?
Brush Type 2’s were built like battleships by comparison with Sulzer Type 2’s. Very heavy construction.

They were very much mid 1950’s technology and diesel loco design was rapidly evolving at the time.

Production at Loughborough ran from 1957-1962 and by the time the last ones were built they were underpowered compared to the competition. Hence the Mirrlees power unit output was progressively pushed up from 1250hp to 1365hp to 1600hp during the production run to try and compete.
 

Harvester

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Brush Type 2’s were built like battleships by comparison with Sulzer Type 2’s. Very heavy construction.

They were very much mid 1950’s technology and diesel loco design was rapidly evolving at the time.

Production at Loughborough ran from 1957-1962 and by the time the last ones were built they were underpowered compared to the competition. Hence the Mirrlees power unit output was progressively pushed up from 1250hp to 1365hp to 1600hp during the production run to try and compete.

Didn’t one of the last batch get an uprated 2000hp engine in 1962. I remember reading that it was trialed on some type 4 diagrams from Finsbury Park that summer.
 

hexagon789

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That was very early days for things we take for granted now, like AC main alternators - iirc there was a practical limit of about 2700bhp into a DC gen before you got too much risk of flashovers. Brush had done a lot of theoretical work on AC transmission in the 60s, but it was all fairly new. Thyristors were developed in the 50s & Brush had actually done a build with AC traction motors in the 60s, but I guess they weren't confident enough to go the full way with Kestrel.
It took quite a while for the thyristor to see widespread use. One of the first uses I can think of is on the Austrian Trans-Alpin EMUs - the rheostatic braking was thyristor rather than traditional resistance controlled. In Britain I assume the 87/1 was the first use.


The point about body design is a good one, there was some “steam age” thinking applied when designing early diesels and I suspect chassis etc. were over engineered. There were certainly no lightweight materials, stressed skins etc. in those days!
For the same nominal weight as Kestrel you had the mere 2,000hp 40s - built like tanks!

Why were the 31s so much heavier, not just compared to 25s but to the other DE type 2 classes too?
Construction materials and perhaps intended use? The 25s being designed to be able to be used on more restricted lines with lower RA

Didn’t one of the last batch get an uprated 2000hp engine in 1962. I remember reading that it was trialed on some type 4 diagrams from Finsbury Park that summer.
That sounds familiar, but I can't offer anything further off the top of my head
 

ac6000cw

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Think first diesel locos with AC motors were DSB ME1500s built in 1980s.
That's my understanding as well, using traction equipment from Brown-Boveri (BBC, later ABB after merging with ASEA).

This was roughly contemporary with the DB class 120 electric loco introduction, which also featured 3-phase AC-drives (at much higher power levels).

For diesels, in the late 1980s/early 1990s EMD (with Siemens) produced the F69PHAC and SD60MAC demonstrators using Siemens traction equipment. The production SD70MAC arrived in 1993.

Expect the control electronics weren't sufficiently developed at the time of Kestrel to allow a reliable AC drive.
Correct - even by the early 1980s, high power traction inverters were still pretty complex and expensive, and would have been impractical (too complex/large/expensive) in 1967 when Kestrel was constructed.
 

Clarence Yard

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Didn’t one of the last batch get an uprated 2000hp engine in 1962. I remember reading that it was trialed on some type 4 diagrams from Finsbury Park that summer.

D5835. That really pushed the design to it’s limits!

It had rad grills at both ends, leading to comments it was the only one with two No 1 ends!
 

Irascible

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That's my understanding as well, using traction equipment from Brown-Boveri (BBC, later ABB after merging with ASEA).

This was roughly contemporary with the DB class 120 electric loco introduction, which also featured 3-phase AC-drives (at much higher power levels).

For diesels, in the late 1980s/early 1990s EMD (with Siemens) produced the F69PHAC and SD60MAC demonstrators using Siemens traction equipment. The production SD70MAC arrived in 1993.


Correct - even by the early 1980s, high power traction inverters were still pretty complex and expensive, and would have been impractical (too complex/large/expensive) in 1967 when Kestrel was constructed.
Hawk had thyristor controlled squirrel-cage motors - don't know when it rolled out ( early 60s sometime ), there is little easily available info on the project, more is the pity. There must have been similar projects elsewhere at the time. It is a little surprising how big a gap between experimental installation & production versions there is given the rate of development in electronics over the period.

This might be worth its own thread, I think.
 

lakeland844

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I think you are all right in that the work for them gradually disappeared as freight declined and more powerful motive power became available for what was left.

During the 1970s/early 1980s the North East depots maintained an allocation throughout.
There always seemed to be a few of them parked up ready for action in the sidings at Tyne Yard !

Gateshead had 2 or 3 ETH examples (31406/408/418) whose main role appeared to be the parcels traffic along the Coast line through Sunderland and Hartlepool and on to Teesside. They were also fairly staple motive power for the coast line portion of the East Coast sleeper that served Sunderland in the 1970s leaving Sunderland at 08.38 and heading through non stop to Newcastle with sleeping cars and 2 or 3 Mk 1 day coaches - it was a useful express working for locals running pretty rapidly between the two cities !

There were occasional parcels trains around the North Tyne Loop (Whitley Bay/Tynemouth) in pre Metro days where a single 31 was a regular performer as well as the trip freight workings to Rowntree factory at Kenton Bank Foot and Callerton ICI on what is now the Metro branch to Newcastle Airport - they also regularly performed trip working along the remains of the Riverside Loop to Swan Hunter and other establishments after passenger trains ended in 1973.

The heaviest work I saw them perform in NE England regularly was the iron ore train from Redcar Ore terminal to the blast furnaces at Workington steel works in West Cumbria - a pair of 31s would haul this along the Tyne Valley to Carlisle on a regular basis making a lot of noise but getting the job done !
It was interesting though that the other regular North East Ore working to Consett from Redcar always seemed to produce a pair of 37s - maybe the gradients on the Consett branch were too much for a pair of 31s !
 

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