Class 31s - the good & bad

[Cowley]

I have heard stories of 31s hitting quite high top speeds due to being quite ‘leggy’ even though they were underpowered. Even reaching three figures at times...
We used to get pairs of 31/4s on rakes of mk3s during summer in the late 1980s. They often had problems with overheating. I think this may have been a problem with them when worked hard?
A pair on a hot August Saturday with 13 on climbing out of Paignton certainly made a lot of slow moving noise.
All mouth and trousers as my mother used to say.

 

[jimm]

In the 1970s I occasionally travelled from Loughborough to Cambridge which was normally DMU. Some of the later runs comprised a 31 and 6 mark 1s from Leicester to Cambridge and vv and they were fine on that. Infinitely better than the purgatory of a Cravens class 105 from Peterborough. I also did a few runs from Moorgate over the widened lines to Welwyn GC around the same time (BR mark 1 non-corridor stock) and they were fine on that too.

Almost anything was better than a Cravens Class 105, units so bad they could make a Pacer look good.

As you say, 31s with no more than half-a-dozen coaches were fine, in much the same way as a 33 was. Hook more coaches on the back and neither type was a sparkling performer, e.g. 33s on Waterloo-Exeter.

Not just any ETH, but massive ETH, with an index of 66, which was about a third of the total power output. Chug chug trundle trundle.

I believe the first 31/4 conversions were done when air-conditioned Mk2 coaches entered service and locos were needed by the Eastern and Western Regions to transfer empty stock between carriage sidings and stations that could drive the air conditioning on long rakes of coaches to get them to the right temperature before passengers got on board, hence the high ETH index. So trundling was not a problem on that sort of work.

The Leeds-based ones were also used for portion working on West Riding of Yorkshire services to Harrogate, Bradford, Halifax and Huddersfield. Only 24 were converted in the first batch, with quite a long gap until another 40 or so were done as part of the drive to end the use of steam heating.

 

[Kneedown]

I remember once, as a young Secondman. My Driver and I had just brought a 31 onto Etches Pk one fine evening. He was in a rush to get off to the "Merry Widows" for some refreshment, so left me to stable and dispose of the loco. I took the battery switch out marginallu before the engine had stopped fully turning, and nearly pooped my pants when the engine roared into life again! This was compounded further when I found out the engine stop button wouldn't now work. After scratching my head I pulled the toggle on the Governor to finally shut it down.
That was how I learned to wait until the engine had stopped fully turning before isolating the bis ( If it was the "knife" type) on a 31!

 

[big all]

i can remember when i was a redhill second man with a redhill driver in norwood down yard siting in a 33 in the early 70s we where beside a 31 and the driver said " i bet we can give that loco a run for it money" and i said as a young upstart " i would hope so as we are 1550 and he is 1470
as an upside a crompton has a decompounding feild over the main gen meaning full power plus a bit 3000 amps then the you dont overload it just reducses load where as 31you need to watch and hold below the overload limit

 

[GrimShady]

Weren't the 31/4s used on Pennine services from Hull during the late 80s early 90s?

 

[dk1]

Drivers would often isolate the ETH after Thetford on the last Birmingham-Norwich services of the day to gain extra power regaurdless of whether the passengers & guard would freeze for the last half hour. This gave it much needed extra umphh & boy did some of the hammer along way over the 70mph line speed.

 

[DarloRich]

Chris Evans was made to look very very silly when he made a similar comment reguarding Norwich which he insisted was flat

the joke when I lived in Great Yarmouth was that Norfolk Constabulary didn't need a helicopter. They just put a man on the roof of the Norwich Union building with a big telescope! Norfolk is flat. That was brought home to me when we lived at Caister and we had to walk uphill to the beach!

 

[Clarence Yard]

A Brush 2 would haul just about anything on the flat but stopping a really heavy load was another matter and there were a few accidents and near misses as a result. A Sulzer 2 would be faster off the blocks but would quickly get winded with a substantial load. In the summer of 1979 the GN "borrowed" a few cl.25 to work the KX-Peterborough trains with the 8 coach Mk 1 "Parly sets" (as we on the GN called them) and those characteristics soon came into play, so much so that the borrowing had to stop, for timekeeping reasons.

Out of KX the Brush 2 was a terrific slogger, even on gradients. From a standing start they used to take the heavy empty sleepers out of Hornsey Waterworks washer up over to the Hertford line and the thrash was heard for a fair distance (!) but they were not a type 3, as the WR found out. They also had a tendency to overheat when going flat out with No 1 end leading. That was down to rad capacity and aerodynamics and there were numerous experiments but the best one was the high speed rad fan mod they did in the 1970's on about a dozen FP machines. On the GN Brush 2's would get used on class 1 trains so this was an ideal testing ground and that mod was, I believe, eventually adopted.

The reason the Brush 2 survived and the Sulzer 2 didn't was mainly down to overhaul costs. The Brush 2 was cheaper to overhaul and had a fairly indestructible engine. It's structure was in better nick and the main electrics also seemed to last longer and needed less works attention.

 

[keith1879]

Weren't the 31/4s used on Pennine services from Hull during the late 80s early 90s?

When the Hazel Grove chord was opened the Hope Valley trains were Class 31 hauled. It made a trip to Sheffield a real treat (and gave Davenport station a regular service of proper (passing) trains).

 

[Ash Bridge]

A Brush 2 would haul just about anything on the flat but stopping a really heavy load was another matter and there were a few accidents and near misses as a result. A Sulzer 2 would be faster off the blocks but would quickly get winded with a substantial load. In the summer of 1979 the GN "borrowed" a few cl.25 to work the KX-Peterborough trains with the 8 coach Mk 1 "Parly sets" (as we on the GN called them) and those characteristics soon came into play, so much so that the borrowing had to stop, for timekeeping reasons.

Out of KX the Brush 2 was a terrific slogger, even on gradients. From a standing start they used to take the heavy empty sleepers out of Hornsey Waterworks washer up over to the Hertford line and the thrash was heard for a fair distance (!) but they were not a type 3, as the WR found out. They also had a tendency to overheat when going flat out with No 1 end leading. That was down to rad capacity and aerodynamics and there were numerous experiments but the best one was the high speed rad fan mod they did in the 1970's on about a dozen FP machines. On the GN Brush 2's would get used on class 1 trains so this was an ideal testing ground and that mod was, I believe, eventually adopted.

The reason the Brush 2 survived and the Sulzer 2 didn't was mainly down to overhaul costs. The Brush 2 was cheaper to overhaul and had a fairly indestructible engine. It's structure was in better nick and the main electrics also seemed to last longer and needed less works attention.

A very interesting post there Clarence Yard, most informative, many thanks!

 

[randyrippley]

....................The reason the Brush 2 survived and the Sulzer 2 didn't was mainly down to overhaul costs. The Brush 2 was cheaper to overhaul and had a fairly indestructible engine. It's structure was in better nick and the main electrics also seemed to last longer and needed less works attention.

was there an asbestos factor as well? Some of the Sulzer type 2's clearly had an asbestos problem, did the 31?

 

[Pigeon]

I believe the first 31/4 conversions were done when air-conditioned Mk2 coaches entered service and locos were needed by the Eastern and Western Regions to transfer empty stock between carriage sidings and stations that could drive the air conditioning on long rakes of coaches to get them to the right temperature before passengers got on board, hence the high ETH index. So trundling was not a problem on that sort of work.

Yes, they were intended to match the ETH capability of AC electrics so they could preheat WCML rakes and bring them from Camden to Euston. Fine for that, but painful in passenger service.

One thing I did manage to dig up off the system for concealing all human knowledge was that although they were all index 66 there were something like 3 different methods by which the conversion was achieved, some better conceived than others.

I do think it is a shame that the 33s were not used for the passenger duties that the 31s got instead. Much more lively - I remember being particularly impressed with a 33 on the Welsh Marches line accelerating hard enough to push me back in the seat. Not a common experience with diesels, especially small ones, and unknown with a 31...

 

[jimm]

Yes, they were intended to match the ETH capability of AC electrics so they could preheat WCML rakes and bring them from Camden to Euston. Fine for that, but painful in passenger service.

One thing I did manage to dig up off the system for concealing all human knowledge was that although they were all index 66 there were something like 3 different methods by which the conversion was achieved, some better conceived than others.

I do think it is a shame that the 33s were not used for the passenger duties that the 31s got instead. Much more lively - I remember being particularly impressed with a 33 on the Welsh Marches line accelerating hard enough to push me back in the seat. Not a common experience with diesels, especially small ones, and unknown with a 31...

There just weren't enough Class 33s to go around.

The second batch of 31/4s took the total available up to the mid-60s - whereas there were only 98 Class 33s to begin with and the ones used on the Marches line were cycled to and from Southern Region depots for maintenance via the Portsmouth-Cardiff services.

The 31s were a known quantity to depots all over the Eastern Region in particular, so using the extra ETH variants on services there and close by made sense.

 

[70014IronDuke]

In the early days I think the 31s outperformed on most steam turns they were put on, certainly on the GE. Pretty sure they could equal if not outperform a B1 on similar loads. As I remember, they worked the Cambridge Buffet Expresses CAmbridge - KX along with Baby Deltics, didn't matter which type was on the front.

In 62 or 63, a Tinsley 31 used to be diagrammed for the " Master Cutler" when it ran to KX - Sheffield via Retford, a full Pullman train, IIRC. (Probably only 8 carriages, I suspect, but still, they were heavy, with Commonwealth bogies to boot.) So they were ok-ish, but as pressure mounted on timings, they had nothing in reserve. Then came ETH. They really were not designed to have to cope with that.