What happened to all the 31's?

Lek

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I've been out of the scene for years, recently rekindled this old pastime, so I bought a few books to get me up to speed, namely Colin Marsden's 'Traction Recognition' and Platform 5's 'Locomotives 2021'. There's a whole section on class 31's in the Traction recognition book (no mention of withdrawals), but in this year's Locomotives book it seems there's only one single class 31 remaining in service. As a kid I'd see loads of 31's every day, possibly the most common loco on the reailway, yet they've suddenly disappeared. I can't find any info on why the entire fleet was condemned. Anyone have any info they could share?
 
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birchesgreen

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They basically became old and surplus to requirements, there isn't a lot of work available for Type 2s anymore. There are nearly 30 in preservation so its still pretty easy to see them.
 

ExRes

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One slight update needed to that wikipedia article, 31106 is indeed at ELR being overhauled for a return to the main line, reportedly in September, but is now owned by Hanson & Hall
 

eastwestdivide

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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.
 

Sultan1056

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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.
:lol:
 

dmncf

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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.
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 Why were they not withdrawn earlier?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?
 

37114

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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?
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.
 

hexagon789

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Were they particularly reliable?
Certainly not until re-engined. And even then no more so than the average loco class.



Why were they not withdrawn earlier?
Versatility, they could perform a variety of roles - just not very fast! ;)

Once the engine issues were sorted out they were a fairly reliable Type 2. Also, when referred to as 'underpowered' that often seems to be after ETH fitment; with noting that in their early years they were trusted with crack services such as the Sheffield Pullman out of King's Cross and also the Cambridge Buffet Expresses, the latter only required an 80mph top speed but were still a demanding job.

When ETH was fitted later on, anymore than six coaches and performance was hopeless really. I understand that a single 31 on a summer relief of say 12 or 13 Mk1s would really struggle to make much past 65mph. Probably why they were more common in pairs on those duties and from the mid-1980s onwards in pairs on Summer Saturday workings of WCML front line sets into Devon and Cornwall. Even then a single 47 would outperform them quite easily.
 

EveningStar

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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?
Assured by an ex-Bescot driver from the 1980’s, that given a choice between a class 25 or 31, drivers always took the 25. Hence the 25’s wore out first, leaving the 31’s to be overcome by the skin on a custard.
 

hexagon789

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Assured by an ex-Bescot driver from the 1980’s, that given a choice between a class 25 or 31, drivers always took the 25. Hence the 25’s wore out first, leaving the 31’s to be overcome by the skin on a custard.
25s were a lot lighter (just 73 tons), so unsurprising that 31s were more sluggish with about 30 tons more weight to lug round.
 

Bevan Price

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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.
A big factor was the mass arrival of the Sprinter family, which took over most of the passenger work that 31s were doing.
 

hexagon789

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Presumably because they only have four traction motors spread across four axles, but are too heavy to use a Bo-Bo arrangement. That leaves A1A-A1A as the only option I think(?).
I think weight was the main reason. At 107-113 tons, Bo-Bo was out of the question.
 

hexagon789

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Yes definitely, but you can’t use a Co-Co arrangement with only four traction motors either.
Depends, you do have things such as monomotor bogies to two and three-axle designs powered by a single motor but those don't seem to have found favour in the UK. Though that's not two motors powering three axles, which may or may not exist as a design.
 

47444

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Presumably because they only have four traction motors spread across four axles, but are too heavy to use a Bo-Bo arrangement. That leaves A1A-A1A as the only option I think(?).
I think also wasn't the design based on an earlier export loco that used A1A bogies to weight spread on lightweight railways?
 

SteveM70

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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.

: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.
 

LSWR Cavalier

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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?
 

D5645

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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?
Class 31 maintenance costs were significantly lower than alternative designs.

As the requirement for Type 2 locos reduced then 31’s were retained and replaced the more modern and more numerous Class 25’s.

The fact that 31’s could be fitted with ETH for passenger and mail traffic made them more versatile. This meant they often got used vice ETH fitted Type 4’s on heavy passenger work at times of loco shortages. Lots of thrash but not that much speed.
 

DustyBin

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Depends, you do have things such as monomotor bogies to two and three-axle designs powered by a single motor but those don't seem to have found favour in the UK. Though that's not two motors powering three axles, which may or may not exist as a design.

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!

I think also wasn't the design based on an earlier export loco that used A1A bogies to weight spread on lightweight railways?

Yes I believe this is correct. It was a proven design, just a bit unusual in the UK.

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 design was flawed in that it was too heavy for a Type 2. Having two unpowered axles just to take the weight isn’t a desirable feature really. That said, when you look at what was available at the time and the experiences with other Type 2 locos it could be argued that the weight was more of a trade-off than a flaw…

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.

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!
 

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