Jump to content
 

Difference in performance of class 31 & 37


Foden
 Share

Recommended Posts

23 hours ago, Pandora said:

The traction gearing for 90 mph maximum speed may be the problem, a speed  wasted on  unfitted coal train workings of 16T mineral wagons,  if the 31 had been regeared when the engines were replaced for 60 mph running, would the 31 have been as useful as a Scottish BMRCW class 26 for coal trains?

The first 40 or so Brush 2s were geared for 80 mph not 90, 31418 when first converted to ETH was still an 80 MPH loco.

 

  • Agree 2
  • Informative/Useful 1
Link to post
Share on other sites

On 01/12/2019 at 19:47, adb968008 said:


they were pretty diabolical in the late 1980’s early 1990’s.

I think they only survived due to strength in numbers..

24/25’s/27’swere equally knackered but Sulzer power was on its way out with 45/46’s... remember 47’s were called duffs too for a reason.

 

i’m surprised class 26’s didnt replace 31’s, but there werent enough of them about, which meant later scenes of class 33’s in Scotland.

 

fwiw... 33’s have fared better in privatisation and preservation, even today theres more overall 33’s both mainline registered and actually in working order than class 31’s... A poor 33 was always better than a good 31 whenever Ive seen them.

Is it true that the Southern looked after their class 33 locos to a high standard, such as calling them to Works for overhaul at relatively low engine hours compared with other regions and their diesel fleets?

Edited by Pandora
Link to post
Share on other sites

  • RMweb Premium
On ‎01‎/‎12‎/‎2019 at 19:31, The Stationmaster said:

The original Mirrlees engines in the Brush Type 2 clearly fell out of favour for some reason hence them being re-engined with the 1.470 hp EE engine.

 

The Mirrlees engines developed a range of cracking around the crankcase, which was difficult and costly to repair. These were first noticed on the uprated engines (1600hp iirc and 2000hp) fitted to a few of the brush 2's, and although the originally rated engines hadn't really started to show the same issues, the BRB decided that they would at some point. As they were also a non-standard (ie EE or Sulzer) engine, it was decided to re-engine with something that was bullet proof (the EE lump) and then sell the original engines back to Mirrlees, Bickerton and Day, who reconditioned them and sold them on again, mainly for use in trawlers.

Interesting the same EE lump was also considered for fitting to the Metro-Vic co-bos.....

 

Andy G

  • Like 2
  • Informative/Useful 5
Link to post
Share on other sites

12 hours ago, Pandora said:

Is it true that the Southern looked after their class 33 locos to a high standard, such as calling them to Works for overhaul at relatively low engine hours compared with other regions and their diesel fleets?

Well, they were used to keeping Bulleid Pacifics working :P

Link to post
Share on other sites

  • RMweb Gold
5 hours ago, uax6 said:

 

The Mirrlees engines developed a range of cracking around the crankcase, which was difficult and costly to repair. These were first noticed on the uprated engines (1600hp iirc and 2000hp) fitted to a few of the brush 2's, and although the originally rated engines hadn't really started to show the same issues, the BRB decided that they would at some point. As they were also a non-standard (ie EE or Sulzer) engine, it was decided to re-engine with something that was bullet proof (the EE lump) and then sell the original engines back to Mirrlees, Bickerton and Day, who reconditioned them and sold them on again, mainly for use in trawlers.

Interesting the same EE lump was also considered for fitting to the Metro-Vic co-bos.....

 

Andy G

 

Hi Andy,  I have a feeling the engines proposed for the metrovics were 8CSVT the same as used in the northern Ireland hunslets 

Basically an intercooled class 20 engine 

  • Informative/Useful 1
Link to post
Share on other sites

  • RMweb Premium
On 01/12/2019 at 02:55, Foden said:

I’m wondering if drivers noticed much difference in the performance characteristics between ‘standard’ 37s and 31s, which of course had the same engine (albeit non intercooled I believe?)?

 

I’m aware of course that 31s were A1A configuration, so I imagine traction was less with the 31, and I also know that 31/4 had issues regarding ETH power never being available for traction regardless of whether ETH was being used.

Would have thought that the power difference had more to do with it.

The Class 37 engine was around 20% more powerful, yet weighed a handful of tons less, so no wonder the overall performance was like chalk & cheese.

Link to post
Share on other sites

On 01/12/2019 at 09:33, Swindon 123 said:

To true The Johnster. By the time I was working at Hereford from the mid 80's, that could be said about any DMU maintained by Canton. I had quite a few failures with Canton based DMU's of all types. Mind you Bristol based ones weren't much better, the B9xx sets being considered right dogs by Hereford drivers.

 

Paul J.

I get the impression that Canton's reputation is no better now (or has it closed recently)

Link to post
Share on other sites

Some comments from an intermittant teenage train-recorder....

 

I knew them on Transpennine South trains from Grimsby to Manchester as 31/4s , initially 4 car later 5 car and IM locos. Once they got a chance to shift they looked like mainline locos . But sustained gradients from a start were a bit of a struggle - out of Sheffield they would struggle down to 50mph before reaching the summit on the Hope Valley and in the other direction it was a long battle for speed under full power from the Hazel Grove chord up towards Chinley. The repeated start/stop between Doncaster and Sheffield was clearly demanding especially with 5 on

 

I also remember 31 242 with a late Skegness - Cambridge Saturday train (8 or 9 Mk1s) running down Stoke bank at just on 90mph - which is about as fast as was comfortable in the Mk1s behind...

 

The general impression was that IM looked after their 31s and got decent reliability, whereas MR locos on the Birmingham/Norwich trains (5 car) had a reputation for regular failure ,  and a habit of going up in flames 

  • Informative/Useful 2
Link to post
Share on other sites

7 hours ago, kevinlms said:

Would have thought that the power difference had more to do with it.

The Class 37 engine was around 20% more powerful, yet weighed a handful of tons less, so no wonder the overall performance was like chalk & cheese.

If the ETH is turned off, the power that was been sapped by it is available for traction. It is amazing with the ETH at full load how much is sapped away, seen the traction power disappear to quite a low level when I witnessed a 31/4 on the load ban at Doncaster.

 

Lots of driver used to turn the ETH off when pulling away from some stations.

 

 

Edited by 45125
  • Like 1
  • Informative/Useful 2
Link to post
Share on other sites

On 03/12/2019 at 18:28, Pandora said:

Is it true that the Southern looked after their class 33 locos to a high standard, such as calling them to Works for overhaul at relatively low engine hours compared with other regions and their diesel fleets?

Certainly in the early years, Class 33 mileage was well below that of similar classes on other regions. Also their miles per casualty and availability statistics in the 1960s were not brilliant. Something that i discuss in my forthcoming Class 33 book.

  • Like 1
  • Informative/Useful 1
Link to post
Share on other sites

  • RMweb Gold
1 hour ago, 45125 said:

If the ETH is turned off, the power that was been sapped by it is available for traction. It is amazing with the ETH at full load how much is sapped away, seen the traction power disappear to quite a low level when I witnessed a 31/4 on the load ban at Doncaster.

 

Lots of driver used to turn the ETH off when pulling away from some stations.

 

 

 

The first twenty 47s had a spring loaded position X beyond full power when first built,  this cut out the ETH to give brief periods of extra power 

  • Informative/Useful 3
Link to post
Share on other sites

  • RMweb Premium

I've seen  it mentioned that ETH took about 300-400hp out of the loco performance, depending on the ETH load of course.

The electrical load on the generator can apply a significant torque against the rotation of the engine, which then slows down or requires more power to keep up the revs.

  • Informative/Useful 1
Link to post
Share on other sites

  • RMweb Gold
20 minutes ago, keefer said:

I've seen  it mentioned that ETH took about 300-400hp out of the loco performance, depending on the ETH load of course.

The electrical load on the generator can apply a significant torque against the rotation of the engine, which then slows down or requires more power to keep up the revs.

 

I've had a couple of class 20s over the years stall, where field diverts have gone in but not come out when required and the engine cant cope with the load and slows the engine so much the low oil pressure governor shuts the engine down 

Basically the same as driving your car up a steep hill but not bothering to change down 

Link to post
Share on other sites

  • RMweb Gold

You may be confusing eth with air conditioning, which was claimed to reduce the power at the rail by about 400hp for 47/4s on the mk2e WR stock.  Loads went down from 10 to 9 in order to maintain the timetable.  Or so they told us on the course to learn how to turn it on and off in the coaches.

Edited by The Johnster
Link to post
Share on other sites

  • RMweb Premium
15 minutes ago, russ p said:

 

I've had a couple of class 20s over the years stall, where field diverts have gone in but not come out when required and the engine cant cope with the load and slows the engine so much the low oil pressure governor shuts the engine down 

Basically the same as driving your car up a steep hill but not bothering to change down 

 

I know some locos had the field diverts come in (normally three stages) at fixed speeds on the way up, and drop out again as the speed decreases. Was part of a C exam and above to test them IIRC, and I wonder how new wheels and old wheels affect performance even if the wear compensation is correct. Some of the class 47s were controlled by the load regulator though, so would bring them in depending on engine load and not road speed.

To stick in though I'm thinking welded contacts somewhere, similar to something that did happen on 47s occasionally, where when you pulled the BIS handle up, the resulting load would literally blow the switch apart in a big blue flash (and kill any dodgy battery cells in the process).

 

Back to 31s though, I wonder if the middle carry axle springing went out much between works visits, as if it took too much load it would unsettle the drivers either side it. Could partly explain lack of traction.

  • Like 2
Link to post
Share on other sites

  • RMweb Gold

The problem with 20s is you have two relays voltage raise and voltage lower I can't remember off hand which one is which if failed one gives you low power the other prevents field reversion. 

Trouble is they don't normally fail completely but start by sticking randomly 

Link to post
Share on other sites

57 minutes ago, russ p said:

Going back to 31s , am I right in thinking US  manufacturers have gone back to two motor three axle bogies?  A1A and1B in American parlance 

 

Both GE and EMD have an option for those (GE offers the A1A-A1A while EMD offers B1-1B), but they aren't popular.

 

I don't believe the EMD version went beyond 2 demonstrator units, and the GE offering only amounts to 299 units (275 to BNSF, 24 to FEC) out of thousands of regular C-C units.

Edited by mdvle
  • Informative/Useful 1
Link to post
Share on other sites

5 hours ago, Pandora said:

Did the depot Fitters ever fiddle with the 31s, achieving more than rated power by tweaking the fuel injector racks?

 Stratford depot had a reputation for getting more out of their 31's in terms of power output than any other depot, although Finsbury Parks fleet were also kept in good condition, and gave some impressive performances on occasions.

2 hours ago, russ p said:

 

I've had a couple of class 20s over the years stall, where field diverts have gone in but not come out when required and the engine cant cope with the load and slows the engine so much the low oil pressure governor shuts the engine down 

Basically the same as driving your car up a steep hill but not bothering to change down 

The 31's had a bit of a mix and match set up when it came to engine control, with the English Electric engine governor having to match up with original electrical and load regulation equipment. They had a few idiosyncrasy's, such a starting back up again if you took the BIS out to quickly after shutting them down. I also had one that the load regulator and engine governor went out of synch so that when you opened the controller for power, the amps started to rise but the engine revs didn't rise as well, in fact the engine revs got slower and slower until the engine stalled as the load regulator couldn't or wouldn't increase the fuel to the engine. This happened at Bounds Green, so not on the main line, but to get it out of the way, I was at the cab controls, whilst my driver went into the engine room and tried to manually hold open the fuel racks as much as he could. The loco literally kangaroo hopped down the track until we could put it in a siding out of the way. It was the only loco I had that shut the engine down due to excessive wheelslip, although I did have a class 33 once on a Cardiff -Crewe that engine oversped when the 3rd field divert operated.

 

Happy days!

 

Paul J.

  • Like 2
  • Informative/Useful 1
Link to post
Share on other sites

On 30/11/2019 at 17:43, Foden said:

See it’s this apparent huge difference in performance that’s so surprising. On paper the 31 is ‘only’ just short of 300hp down on the 37, indeed two 31s with not far off 3000hp is circa 500hp up on a single 47, yet opinions suggest a single 47 would run rings round a pair of Peds in terms of performance.

 

Like all statistics, it depends how you look at the numbers...

300hp may not look a big difference at first, but it's actually around 17.5%, so is quite a large difference, and  for locos of around the same weight.

Also to be borne in mind, that's the difference in engine output, auxiliaries on the two types will probably be similar, so the difference in power would be solely in traction power, making the gap here even wider.

 

In comparing a pair of 31s with a single 47, a 500hp or 18% increase in power, but for double the weight, and also double the auxiliaries load so not actually so much increase in traction power.

 

As to the difference between the two, the 31 was good for what it was intended for, light work, and had a comfortable cab environment compared to most locos of it's time. The main problem was they were often overloaded on unsuitable work.

 

The 37 on the other hand, was commonly said it would pull the station as well as the train if you tied it on!

One incident I remember, and which actually involved a (rare) failure on one...

At Gateshead, we had a turn with a 37 on the Grangemouth tanks, about 900 tons of them, which we relieved in at Waverley and worked back to Newcastle. I was secondman on this several times.

It usually, with taking a run at it, got over the top of Cockburnspath at around 20mph...

This particular night, unknown to us, it had been brought in from Grangemouth with the (manual) radiator shutters closed. Naturally it wasn't long before it boiled dry, and we came to a stand at Innerwick, when the low water level switch, switched off the engine.

No alternative but to call for assistance. No Problem, the signaler had a down freight in the loop at Grantshouse, he'd get him to leave his train in there and come forward to assist us.

After a short wait then, we see the lights of the assisting engine approaching the emergency crossovers just ahead of us and, to our dismay, realize it's just another 37.

So, he comes in on top, gets tied on etc and we're ready to go...

But, as well as the 900 ton of tanks we now also have another 100 ton of now dead 37 behind us, and with a standing start from Innerwick, which is...

virtually right at the foot of Cockburnspath bank!!

No trouble, our relief 37 was still doing 20 at the top!!

Edited by Ken.W
  • Like 8
  • Informative/Useful 2
Link to post
Share on other sites

  • RMweb Premium
7 hours ago, The Johnster said:

You may be confusing eth with air conditioning, which was claimed to reduce the power at the rail by about 400hp for 47/4s on the mk2e WR stock.  Loads went down from 10 to 9 in order to maintain the timetable.  Or so they told us on the course to learn how to turn it on and off in the coaches.

Fair enough, but I did say depending on load :)

MK1 coaches seem to be ETH index 2 or 3, mk2-2c usually 4 and mk2d-f usually 5. Mk3 saloons are 6.

So non-a/c coaches are still drawing a load (although obviously less than a/c stock) and it made enough of a difference to affect the performance of the locos i.e the need to turn ETH off if the extra power was needed to move the train (or keep it moving)

Link to post
Share on other sites

  • RMweb Gold
On 04/12/2019 at 10:42, kevinlms said:

Would have thought that the power difference had more to do with it.

The Class 37 engine was around 20% more powerful, yet weighed a handful of tons less, so no wonder the overall performance was like chalk & cheese.

The early 31s tapped ETH from the main generator, which meant that regardless of the ETH setting, traction was not available, simple reason being....the coils in the generator used for the traction field were smaller so could generate less power....

 

later 31s used an ETH alternator similar to 45/1s and 47/7, which is why they had the description..."the only locomotive that can heat more coaches than it can pull"

 

its a little unfair to compare a 31 to a 37 because the its the electrical systems which limit it, only the engine was changed when they were re-engined, not the main generator.

 

31s were always in the type 2 power band....

 

a 33 on the other hand had separate ETH generator which is why you could shut it off for a bit more power....but tbh it was negligable.....33s didnt have the ETH rating of a 31 however...

 

 

 

 

  • Informative/Useful 1
Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share

×
×
  • Create New...