Difference in performance of class 31 & 37

[woodenhead]

I can remember Deltics leaving Doncaster initially on one engine then the second would join in once the train was rolling - it was quite noticeable.

[russ p]

When deltics are on charters with AC stock these days they tend to have a generator coach or a second engine as the mk2 aircons MAs aren't keen on deltic flavour ETH

[stewartingram]

In the early 60s I did a few Merrymakers from Cambridge to Blackpool for the lights. One year, around 199-ish, D5616 was the loco all the way - my last non D58xx Brush 2! By that date the route was Cambridge-March-Lincoln-Doncaster then west across the Pennines to Manchester-Preston-Blackpool. I can't remember the exact route, but we usually had 2 portions (from Cambridge & Ipswich) which joined at Ely or March (depending on the route out of Cambridge). On this occasion, D5616 was the loco taking the combined train forward. We usually changed engines at Doncaster; a steam loco was expected (the previous year it was 45562 Alberta) but this time D5616 took us all the way  (and back again, leaving the Blackpool North excursion platforms - which form the present station - around midnight). A long journey for a single 31; my guess is around 12 coaches including a buffet car. I do remember the laborious climb over the Pennines, but the old girl got us there and back ok.

 

Stewart

[roythebus]

Complete and utter tosh on the Deltic engines.

 

Some drivers would use one engine on sleeper trains when speed was not of the essence, it made a quieter ride for the loco crew to have the trailing end engine running. Same with parcels/ecs workings. We occasionally used them on ECS round the Bermuda Triangle of Ferme Park and Bounds Green and ran on one engine. 

 

Once both engines were running, the driver could not select from the cab which one provided power. They both ran, they both provided power. Both engines were usually required to move a train out of KX, the slipping etc depended on the driver or secondman's skill at shutting the power handle as soon as the revs built up. That could only be learnt by experience. 

 

ETH could indeed be shut down from the cab and sometimes did get shut off when extra power was required.

 

The 47401-420 batch provided DC power for ETH, they were known amongst the crews as "the generators". I think they were all allocated to the ECML and the FP locos could give the Deltics a run for their money.

[stovepipe]

Says you.... though actually you haven't contradicted anything that's been said. 

 

For my part I'm directly quoting someone involved with them for 35 years, but hey what does he know?

[kevinlms]

11 hours ago, roythebus said:

Complete and utter tosh on the Deltic engines.

 

Some drivers would use one engine on sleeper trains when speed was not of the essence, it made a quieter ride for the loco crew to have the trailing end engine running. Same with parcels/ecs workings. We occasionally used them on ECS round the Bermuda Triangle of Ferme Park and Bounds Green and ran on one engine. 

 

Once both engines were running, the driver could not select from the cab which one provided power. They both ran, they both provided power. Both engines were usually required to move a train out of KX, the slipping etc depended on the driver or secondman's skill at shutting the power handle as soon as the revs built up. That could only be learnt by experience. 

 

ETH could indeed be shut down from the cab and sometimes did get shut off when extra power was required.

 

The 47401-420 batch provided DC power for ETH, they were known amongst the crews as "the generators". I think they were all allocated to the ECML and the FP locos could give the Deltics a run for their money.

Deltics and Class 47401-47420. What does this have to do with Class 31 vs Class 37?

 

NOTHING at all!

[45125]

On 07/12/2019 at 10:02, Baby Deltic said:

I would imagine that after what happened to 1562 it would have been a no-no to set engine governors and fuel racks beyond the normal ratings.

When a loco is set up and load banked there is graph it is set too. On this graph there is an optimum setting which is what you try to achieve, however it is not always possible to get this spot on due variable of the governor, fuel pumps, injectors, compression etc. so there is band either side of the optimum, quite often the bottom up can be set up correctly (ie notch on) but the top up can be out either low or high. On the very odd occasion it will fall outside of the band, and no amount of tweaking will put it right, this why some locos perform better than others. I have seen several locos on the load bank were a great deal more horse power is available than the rating, some times more than 400hp.  It is possible to set the fuel rack up wrong on a 31 if you use the wrong gauge.

 

[Baby Deltic]

17 minutes ago, 45125 said:

When a loco is set up and load banked there is graph it is set too. On this graph there is an optimum setting which is what you try to achieve, however it is not always possible to get this spot on due variable of the governor, fuel pumps, injectors, compression etc. so there is band either side of the optimum, quite often the bottom up can be set up correctly (ie notch on) but the top up can be out either low or high. On the very odd occasion it will fall outside of the band, and no amount of tweaking will put it right, this why some locos perform better than others. I have seen several locos on the load bank were a great deal more horse power is available than the rating, some times more than 400hp.  It is possible to set the fuel rack up wrong on a 31 if you use the wrong gauge.

 

1562 was deliberately tweaked by Stratford and it blew up destroying the loco. It’s the only diesel loco written off in BR history for reasons other than accidental collision or fire damage.

[45125]

10 minutes ago, Baby Deltic said:

1562 was deliberately tweaked by Stratford and it blew up destroying the loco. It’s the only diesel loco written off in BR history for reasons other than accidental collision or fire damage.

It wasn't completely destroyed, it was the amount of damage done by the explosion and subsequent fire damage rendered it uneconomic to repair , the monocoque construction of the body saw to this.

[russ p]

15 minutes ago, 45125 said:

It wasn't completely destroyed, it was the amount of damage done by the explosion and subsequent fire damage rendered it uneconomic to repair , the monocoque construction of the body saw to this.

 

Was that the loco where the engine ran away?  Isn't there a roll pin somewhere on a 47s fuel rack linkage that if it comes out gives one bank full fuel and obviously the overspeed cant shut the rack 

[Regularity]

On 01/12/2019 at 14:05, Steven B said:

Class 31s lingered on long after the other Type 2s so they couldn't have been all bad. 

Class 25s had blue asbestos: 31s didn't.

Also, the traction motors on class 25s were designed by AEI with export in mind, to potentially lines with metre gauge, so they were quite small and the maximum rating wasn't much above the continuous rating, so they were prone to flashovers and could run "with a leg out", i.e. with only 3 motors and therefore only 75% of available power at the rail.

Finally, not sure there was much room to fit ETH into a 25 (maybe with a generator, per class 27?)

That's 3 reasons why the 25s went...

 

And all in all, the better reliability of a "downrated class 37" prime mover made the choice inevitable, even if the 31s were were overweight and carrying it around on 50% more axles than a Bo-Bo: that's regardless of any preference for EE versus Sulzer.  

 

As has been stated, given the right duties and the appropriate level of maintenance (and presumably the right amount of money spent on it?) 31s could work well, as did Stratford's. But in the wrong places, and overworked with poor maintenance, they were not so good. 37s on the other hand are simply rugged, and all of their weight is used in transferring power to the rail.

 

It's odd, but as well as preferring (understandably, perhaps) to keep work for their own workshops, some private loco builders seem to have lost out. Lion was a BRCW design, but the 47s were built by Brush, and the BRCW 26 and 33 were better than the 25s and 27s. In hindsight, BR could have run the whole network with a few shunters and classes 20, 33, 37 and 47 plus (later) HSTs and AC electrics.

[Baby Deltic]

1 hour ago, russ p said:

 

Was that the loco where the engine ran away?  Isn't there a roll pin somewhere on a 47s fuel rack linkage that if it comes out gives one bank full fuel and obviously the overspeed cant shut the rack 

 

I remember reading an article  in one of the tabloid rags that a railway enthusiast sabotaged a class 47 because they were worried it might be used on their rail tour instead of the rostered engine. I think they must have jammed the fuel rack so the over-speed trip wouldn't work as you say. From what I remember the driver started it up and the engine ran away and blew up. The driver had to literally jump out of the cab before it blew. BR had to rebuild the power unit at a cost of about £150,000 at that time if I remember correctly.

 

1562 was uprated as part of an 'experiment' by BR to uprate a Sulzer 12LDA28C for whatever reason. The loco ran ok for a little while until one night in 1971 when it was accelerating away from Ipswich on a LLS - NR service. It got to Haughley junction when the engine exploded. The force of the explosion blew the engine room door off it hinges, striking driver Harry Hendry and breaking his arm. Hendry had to jump out pretty quick as there was a serious fire afterwards which damaged the loco beyond repair. It was towed off to Crewe and quietly scrapped.

[Baby Deltic]

1 hour ago, 45125 said:

It wasn't completely destroyed, it was the amount of damage done by the explosion and subsequent fire damage rendered it uneconomic to repair , the monocoque construction of the body saw to this.

 

Just a figure of speech. The fire caused by the explosion did for it.

[slilley]

40 minutes ago, Regularity said:

Class 25s had blue asbestos: 31s didn't.

Also, the traction motors on class 25s were designed by AEI with export in mind, to potentially lines with metre gauge, so they were quite small and the maximum rating wasn't much above the continuous rating, so they were prone to flashovers and could run "with a leg out", i.e. with only 3 motors and therefore only 75% of available power at the rail.

Finally, not sure there was much room to fit ETH into a 25 (maybe with a generator, per class 27?)

That's 3 reasons why the 25s went...

 

And all in all, the better reliability of a "downrated class 37" prime mover made the choice inevitable, even if the 31s were were overweight and carrying it around on 50% more axles than a Bo-Bo: that's regardless of any preference for EE versus Sulzer.  

 

As has been stated, given the right duties and the appropriate level of maintenance (and presumably the right amount of money spent on it?) 31s could work well, as did Stratford's. But in the wrong places, and overworked with poor maintenance, they were not so good. 37s on the other hand are simply rugged, and all of their weight is used in transferring power to the rail.

 

It's odd, but as well as preferring (understandably, perhaps) to keep work for their own workshops, some private loco builders seem to have lost out. Lion was a BRCW design, but the 47s were built by Brush, and the BRCW 26 and 33 were better than the 25s and 27s. In hindsight, BR could have run the whole network with a few shunters and classes 20, 33, 37 and 47 plus (later) HSTs and AC electrics.

 

If you look on this forum, there is plenty of information on why BRCW with LION missed out to Brush and D1500. BRCW actually came with the proverbial gnat's crotchet of getting the first order. Class 47 50 Years of Locomotive History has all the detail.

[russ p]

47 minutes ago, slilley said:

 

If you look on this forum, there is plenty of information on why BRCW with LION missed out to Brush and D1500. BRCW actually came with the proverbial gnat's crotchet of getting the first order. Class 47 50 Years of Locomotive History has all the detail.

 

Are you getting that book reprinted Simon? 

[Regularity]

1 hour ago, slilley said:

 

If you look on this forum, there is plenty of information on why BRCW with LION missed out to Brush and D1500. BRCW actually came with the proverbial gnat's crotchet of getting the first order. Class 47 50 Years of Locomotive History has all the detail.

Fair point, but OT to the discussion in this thread.

Are you promoting the book, perchance?

[Titan]

1 hour ago, Baby Deltic said:

1562 was uprated as part of an 'experiment' by BR to uprate a Sulzer 12LDA28C for whatever reason. The loco ran ok for a little while until one night in 1971 when it was accelerating away from Ipswich on a LLS - NR service. It got to Haughley junction when the engine exploded. The force of the explosion blew the engine room door off it hinges, striking driver Harry Hendry and breaking his arm. Hendry had to jump out pretty quick as there was a serious fire afterwards which damaged the loco beyond repair. It was towed off to Crewe and quietly scrapped.

 

Does anyone have an idea what it was uprated to?  By that time all class 47's had been reduced to 2,580bhp. Was it simply reset to the original 2,750bhp?  There could be good reason for doing this as a trial, as several other mods to all 12LDA units had been done to improve reliability, including for example phasing the crankshafts differently. Could it have been an experiment to see if returning to 2,750bhp would have been practical after the mods?  Had it been a success would all 47's reverted back to 2,750bhp?  I doubt that it was an unofficial depot mod, just that a Stratford loco was chosen for the experiment.

 

Back on topic, I always thought it curious that the rating of the 31 was 1,470bhp, and that the engine was de-rated.  Since the engine was of the same family fitted to the class 20 and class 40, then it would have had a standard rating of 1,500bhp, not the 1,750bhp of the charge cooled version fitted to the class 37.  De-rating by just 30bhp almost seems like a paper exercise to keep the loco in the type 2 power range.  Otherwise it would have been a pretty weedy type 3...

Edited December 10, 2019 by Titan

[Baby Deltic]

21 minutes ago, Titan said:

 

Does anyone have an idea what it was uprated to?  By that time all class 47's had been reduced to 2,580bhp. Was it simply reset to the original 2,750bhp?  There could be good reason for doing this as a trial, as several other mods to all 12LDA units had been done to improve reliability, including for example phasing the crankshafts differently. Could it have been an experiment to see if returning to 2,750bhp would have been practical after the mods?  Had it been a success would all 47's reverted back to 2,750bhp?  I doubt that it was an unofficial depot mod, just that a Stratford loco was chosen for the experiment.

 

 

 

If they blew it up my guess is they were way above 2750hp. I'll bet they were trying to get a Type 5 rating of about 3000hp. Definitely an official experiment and one which caused a lot of red faces I would have thought because you can bet Sulzer weren't aware of it.

[Baby Deltic]

26 minutes ago, Titan said:

Back on topic, I always thought it curious that the rating of the 31 was 1,470bhp, and that the engine was de-rated.  Since the engine was of the same family fitted to the class 20 and class 40, then it would have had a standard rating of 1,500bhp, not the 1,750bhp of the charge cooled version fitted to the class 37.  De-rating by just 30bhp almost seems like a paper exercise to keep the loco in the type 2 power range.  Otherwise it would have been a pretty weedy type 3...

Remember that a Class 31 has an A1A-A1A wheel arrangement, hence only four traction motors instead of the usual six for a six axle loco, therefore the engine output would need to suit the generator and traction motor ratings for the equipment on the locomotives.

Edited December 10, 2019 by Baby Deltic

[Titan]

14 minutes ago, Baby Deltic said:

Remember that a Class 31 has an A1A-A1A wheel arrangement, hence only four traction motors instead of the usual six for a six axle loco, therefore the engine output would need to suit the generator and traction motor ratings for the equipment on the locomotives.

 

On the other hand the same traction equipment was used at 1,600bhp and 2,000bhp with the uprated Mirlees engines, the latter being put on class 40 diagrams...

[Baby Deltic]

3 minutes ago, Titan said:

 

On the other hand the same traction equipment was used at 1,600bhp and 2,000bhp with the uprated Mirlees engines, the latter being put on class 40 diagrams...

 

Fair point. Mind you, it was an SVT and not a CSVT like on a class 37, so maybe they wanted it to run at a 'non-stressed' rating with plenty of engine hours between overhauls.

 

[Titan]

5 minutes ago, Baby Deltic said:

 

Fair point. Mind you, it was an SVT and not a CSVT like on a class 37, so maybe they wanted it to run at a 'non-stressed' rating with plenty of engine hours between overhauls.

 

 

I think the reason was because the SVT ran at lower rpm than the Mirlees. Not only does this mean that the cooling fan on the generator is running at lower rpm so less cooling, but lower rpm means lower voltage and higher current (and hence more heat in the windings) for similar horsepower. Hence at SVT rpm 1,470bhp was all that could be got reliably.

Edited December 10, 2019 by Titan

[Davexoc]

2 hours ago, Regularity said:

Also, the traction motors on class 25s were designed by AEI with export in mind, to potentially lines with metre gauge, so they were quite small and the maximum rating wasn't much above the continuous rating, so they were prone to flashovers and could run "with a leg out", i.e. with only 3 motors and therefore only 75% of available power at the rail.

 

There were plenty of flashovers on Brush and EE traction motors too. EE main generators in 31s and 50s also regularly went bang, one 31 on a LE test run OC - Slough one evening lit the No.2 cab up quite spectacularly as we took power crossing over to the down main. Not too serious, whereas a 50 would shed all it's mica insulation, blow chunks out of the brush boxes and burn tails away, leaving a 'birds nest' in the bottom.

 

2 hours ago, Baby Deltic said:

1562 was uprated as part of an 'experiment' by BR to uprate a Sulzer 12LDA28C for whatever reason. The loco ran ok for a little while until one night in 1971 when it was accelerating away from Ipswich on a LLS - NR service. It got to Haughley junction when the engine exploded. The force of the explosion blew the engine room door off it hinges, striking driver Harry Hendry and breaking his arm. Hendry had to jump out pretty quick as there was a serious fire afterwards which damaged the loco beyond repair. It was towed off to Crewe and quietly scrapped.

 

Just wonder if it was fuel leakage, as the high pressure pipes had a tendancy to split and pump fuel into top end which diluted the lube oil and anything over 5% fuel was an immediate oil change. I did have one that came in as it kept shutting down on low oil pressure, and when tested the oil was 15% fuel, so could have blown the crankcase apart given the right/wrong conditions. IIRC four rocker covers and sets of valve gear were absolutely spotless when the covers were removed.......

[slilley]

1 hour ago, Regularity said:

Fair point, but OT to the discussion in this thread.

Are you promoting the book, perchance?

It is OT to the discussion in this thread but as LION and its history was mentioned, I thought i would point people elsewhere if they wanted to catch up with that story. It is a bit late to promote Class 47 50 Years of Locomotive History as it has been out of print for some time now.

[slilley]

1 hour ago, russ p said:

 

Are you getting that book reprinted Simon? 

 

 OPC who were part of Ian Allan were the original publishers. Now all of that is owned by Crecy. I did raise the question with them a while ago about a reprint, purely reprinting the original book, but not had a response. I have been busy with other projects one of which will hopefully come to fruition next year.