ETH Fitted Class 31 Performance

[RichmondCommu]

G'day everyone,

Way back in 1984 a friend and I had the privilege of being allowed into the cab of 31411 at Manchester Piccadilly before it headed off to Sheffield. Having recently taken over from the trans-pennine DMU's we were curious to ask the driver what he thought of his charge. Not much (or at least that's what I can type here) came the reply. Essentially the driver reckoned that four mk2 coaches (incidentally the load that afternoon) was ideal and that it would struggle with any more. He gave a further explanation by saying that the ETH conversion robbed the loco of around a third of its power from something that already couldn't pull the skin off a rice pudding.

However I have a photograph taken of 31412 a year earlier with six Mk2 carriages attached at Thetford on a Norwich - Birmingham train.

On the basis of the above was the driver in Manchester all those years a go right or was he perhaps just wishing for a class 47 instead?

Your thoughts / questions would be very much appreciated.

Kind regards,

Richmond Commuter!

 

[Ash Bridge]

Purely from a laymans point of view, I wonder if the gradient profile of the Hope Valley Line especially from the Manchester direction would present more of a challenge to a 31 compared to Norwich - Birmingham?

 

[RichmondCommu]

Purely from a laymans point of view, I wonder if the gradient profile of the Hope Valley Line especially from the Manchester direction would present more of a challenge to a 31 compared to Norwich - Birmingham?

Well that's a very good point when you think about the climb up to Cowburn Summit. I've got a photo of a class 31 setting off from Scarborough with six coaches but I'm guessing the route to Leeds was on the flat side as well.

 

[edwin_m]

It's around 1 in 90-100 from New Mills South Junction up to the portal of Cowburn Tunnel, then 1 in 150 most of the way to the other end. I don't have profiles to hand for the route via Marple. But Birmingham-Norwich isn't totally flat either - there are climbs at around 1 in 125 between Norwich and Wymondham and between Nuneaton and Water Orton.

 

[Ash Bridge]

I'm genuinely surprised to learn that there are such grades in Norfolk, I'll have to confess l was also under a similar impression as RichmondCommu mentions about Scarborough to Leeds, I wonder if poor railhead conditions inside the lengthy tunnels of Cowburn and Totley also seriously impeded the class 31s performance on the route?

 

[Hairy Bear]

Having worked the Norwich - Birminghams they were ok with 5 coaches. Anymore and they would, t keep time. They had a hard time on the Norwich,s not being lovingly cared for by March depot.As for eth robbing it of a third of power, utter rubbish. The supply came off a separate winding on the gen so not affecting the traction.

 

[D5645]

Hairy Bear is correct regarding the ETS supply from a 31/4.

There is lots of nonsense talked about 31's but in reality they are a heavy Type 2 design so performance can be modest at times when ETS is being provided.

The eastbound climb up the Hope Valley away from New Mills South Junction was a challenge but uphill speeds were typically in the 45-50 mph range with load 5 during the May 1984-May 1986 period.

Of course from May 1986 the Hazel Grove chord was opened so you had a faster run up to the climb.

Old school 31 bashers will often refer to SGS (Standard Goyle Speed) which is 76mph. This refers to the typical maintained speed achieved on load 6 with ETS being supplied.

 

[edwin_m]

Having worked the Norwich - Birminghams they were ok with 5 coaches. Anymore and they would, t keep time. They had a hard time on the Norwich,s not being lovingly cared for by March depot.As for eth robbing it of a third of power, utter rubbish. The supply came off a separate winding on the gen so not affecting the traction.

If the engine is going flat out and the ETH is taking some power then surely there will be that much less power available for traction?

 

[RichmondCommu]

Hairy Bear is correct regarding the ETS supply from a 31/4.

There is lots of nonsense talked about 31's but in reality they are a heavy Type 2 design so performance can be modest at times when ETS is being provided.

The eastbound climb up the Hope Valley away from New Mills South Junction was a challenge but uphill speeds were typically in the 45-50 mph range with load 5 during the May 1984-May 1986 period.

Of course from May 1986 the Hazel Grove chord was opened so you had a faster run up to the climb.

Old school 31 bashers will often refer to SGS (Standard Goyle Speed) which is 76mph. This refers to the typical maintained speed achieved on load 6 with ETS being supplied.

Many thanks for this. In the times I saw a class 31 running through the Hope Valley I only ever saw four coaches running behind the loco but on average I guess that was no more than once a month. Were five coaches typical on that route? Occasionally I would see a full brake as part of the consist and on a very rare occasion a mk2d as well.

 

[RichmondCommu]

Having worked the Norwich - Birminghams they were ok with 5 coaches. Anymore and they would, t keep time. They had a hard time on the Norwich,s not being lovingly cared for by March depot.As for eth robbing it of a third of power, utter rubbish. The supply came off a separate winding on the gen so not affecting the traction.

Many thanks for this, really interesting stuff. Did March MPD have a reputation for poor maintenance or was it just 31s that they struggled with?

 

[D5645]

Many thanks for this. In the times I saw a class 31 running through the Hope Valley I only ever saw four coaches running behind the loco but on average I guess that was no more than once a month. Were five coaches typical on that route? Occasionally I would see a full brake as part of the consist and on a very rare occasion a mk2d as well.

It was a mixture of load 4 and load 5 in the period from May 1984 to May 1987.

These were vacuum braked sets and a mixture of Mark Ones and early Mark Two's.

For the final year of 31 operation from May 1987 to May 1988 everything became air braked sets.

The Liverpool - Sheffield sets were load 4 comprised of 3 Mark Two TSO's plus a Mark One BG.

The Cleethorpes - Liverpool - Yarmouth sets were load 5 comprised of 4 Mark Two TSO's plus a Mark Two BSO.

The odd air conditioned Mark Two did appear from time to time during this final year.

 

[driver_m]

The drivers I work with who signed 31's seem to be of the universal opinion that they were awful. Not one driver had a good thing to say about them.

 

[D6975]

If the engine is going flat out and the ETH is taking some power then surely there will be that much less power available for traction?

True. The notion that the ETH power was magicked out of fresh air and didn't effect the power available for traction is absolute b****cks. You don't have to be a driver to know that, a basic understanding of physics is all that's required. I used to know several Bath Road drivers and they told me that they would turn the EH off when going up inclines like Filton bank or up out of the tunnel.

 

[D5645]

Running with the ETS on definitely affected the performance. It was a common trick to turn off the ETS to gain more traction power for climbing gradients.

The ETS from a 31/4 was provided by an alternator bolted on the end of the main generator.

There was a story that a 31/4 operated on reduced power even when the ETS was turned off. It's even appeared in some books but it is complete rubbish.

The engine governor on a 31/4 is set to a higher idle speed than a 31/1 to assist with maintaining ETS when idling. The two different types of governor have a different coloured band on them to assist maintenance staff identify the correct type.

 

[delticdave]

If the engine is going flat out and the ETH is taking some power then surely there will be that much less power available for traction?

Totally correct, if the ETH generator is being used, then it's taking power from the engine, with less power available to pull the train.

In more enlightened countries, with heavier ETH / HEP loads than we find in the UK (N. American Commuter Trains) it's been normal practice for the locos to be fitted with auxiliary diesel engines & generators.

Amtrak California uses the same set-up, & VIA Rail Canada has rebuilt all it's
F40's with gensets too.

As for 31's in passenger service, I did manage to ride one of the Chester to Blackpool rush-hour trains, with 4 non-aircon Mk 2's, topped & tailed 31's, both providing traction. I didn't time the trains but it felt dreadfully slow.....

Imagine how the original class 30's performed on the Gt. Eastern, or the 31's on the G.N. locals out of Kings X..

 

[Kneedown]

The drivers I work with who signed 31's seem to be of the universal opinion that they were awful. Not one driver had a good thing to say about them.

Only ever worked them on freight, but I can't disagree. All noise, fumes and very little power.
Having said that, I confess to being very disappointed when EMT's plan to put them on the Derby - Crewe's was kicked into the long grass due to extended dwell times.

 

[dewsnapsliding]

I remember being at Mcr Piccadilly platform 13 in the 80s when a Duff on what I assume was a similar service came in and failed. Cue spare 31 coupled up, and a lengthy conversation took place between driver, someone on the platform and others about whether the 31 could take the train forwards. I recall it departing approx 20+ mins late

 

[Cowley]

Also in the 80s and I think into the early 90s there were pairs of 31/4s on holiday trains to Paignton. Some of them were formed of long rakes of mk3 aircons from the WCML. I'm not sure how many coaches but I think it was at least 12 and I remember catching them out of Paignton as they crawled up the bank towards Torquay on full power.
I often wondered what speed they topped Lickey at a couple of hours later...

 

[Ash Bridge]

Also in the 80s and I think into the early 90s there were pairs of 31/4s on holiday trains to Paignton. Some of them were formed of long rakes of mk3 aircons from the WCML. I'm not sure how many coaches but I think it was at least 12 and I remember catching them out of Paignton as they crawled up the bank towards Torquay on full power.
I often wondered what speed they topped Lickey at a couple of hours later...

Probably about 2 hours to Bromsgrove then another 2 from there to Barnt Green
I think the mk3 rakes with DVT were 9 or 10 coaches if I'm not mistaken, they were still working the occasional Saturday Paignton - Manchester services during 2002 although all 47s by then.

 

[Cowley]

Probably about 2 hours to Bromsgrove then another 2 from there to Barnt Green
I think the mk3 rakes with DVT were 9 or 10 coaches if I'm not mistaken, they were still working the occasional Saturday Paignton - Manchester services during 2002 although all 47s by then.

Ah right thanks for that. They always seemed quite long, the named Pullman mk3s used to appear from time to time too.

 

[CosherB]

Having worked the Norwich - Birminghams they were ok with 5 coaches. Anymore and they would, t keep time. They had a hard time on the Norwich,s not being lovingly cared for by March depot.As for eth robbing it of a third of power, utter rubbish. The supply came off a separate winding on the gen so not affecting the traction.

Just where do you get this b*!!*cks information from? :roll:

 

[dgl]

Yes, but the rules of thermodynamics don't apply to class 31's!

Sent from my Lumia 625 using Tapatalk

 

[daikilo]

Yes, but the rules of thermodynamics don't apply to class 31's!

Probably more energy management i.e. energy from engine drives the shaft on which the generator is placed. No matter how the windings are distributed, you can only take off so much electrical energy before you cause the engine to slow whether it be simple traction energy or the combination of that and "hotel power".

I would be surprised however if the value for ETH was 30% of the total with only 4/5 coaches.

 

[KevinTurvey]

To be honest I never really noticed a drop in performance when the heating was on - 3 or 4 mk1s ETH of 4 is not a massive electrical load. I never experienced a long train with them. Where I thought 31's really struggled was going uphill.
When they used to do the Wigan - Liverpool locals I can recall it taking ages climbing out of Wigan, and some drivers having real trouble getting the train re-started from Bryn and Thatto Heath especially when the rails were wet, even with just the 4 coaches.
However, when doing the Liverpool - Sheffield trains they did used to get up a fair turn of speed on some of the more level stretches.

 

[randyrippley]

This story about the ETH setup on the early 31/4 conversions causing a permanent power drain even with the ETH "off" has been around for years - from memory its even mentioned in the Wiki entry (or was). Seems some of the later conversions were wired differently and allowed full power delivery when the ETH was off.

Funny thing is, every time I rode behind a 31/4 it was the same loco: 31444 and that seemed to go like a rocket. Easily cruising at 90 on a sunday relief on the GW main line Bristol > Reading before heading north to Birmingham (admittedly with a flyweight 4 coaches plus parcels van). Later rode behind it both in the SW and NW and power never seemed to be an issue for it. Was there something different about that one?

 

[RichmondCommu]

To be honest I never really noticed a drop in performance when the heating was on - 3 or 4 mk1s ETH of 4 is not a massive electrical load. I never experienced a long train with them. Where I thought 31's really struggled was going uphill.
When they used to do the Wigan - Liverpool locals I can recall it taking ages climbing out of Wigan, and some drivers having real trouble getting the train re-started from Bryn and Thatto Heath especially when the rails were wet, even with just the 4 coaches.
However, when doing the Liverpool - Sheffield trains they did used to get up a fair turn of speed on some of the more level stretches.

For what its worth (and I appreciate that it may not make any difference at all) on the Hope Valley services the coaches were Mk2s and not Mk1s.

Please understand that I did not mean to be pedantic!

 

[Cowley]

Please understand that I did not mean to be pedantic!

Gettit? Ah never mind.

 

[RichmondCommu]

Gettit? Ah never mind.

Yes very good

 

[route:oxford]

So what made the Class 31 so utterly awful and why keep building them for over a decade?

 

[LAX54]

The 31's also used to work the daily Yarmouth to London services (on the Nch to Yar portion) I recall talking to a Driver once and asked why they were always a little late, he told me that there were two choices, get to Norwich or Yarmouth near enough to time and have the ETH turned off, or keep the passengers warm, and arrive well late !