Performance of "lumbering" Cl 40s and other early BR diesels

[70014IronDuke]

It would be interesting to compare that with the performance of 10203 over the same route in the 50s. The ACE was loaded to 13 usually.

I thought there were some logs of the Bulleid diesels on the Southern Railway website here

www.semgonline.com/home.html - But I haven't been able to find them.

I think all three of these locos were used on the LSWR and SEC lines (including the Golden Arrow - seemingly regardless of the quite significant differences in power output.)

I'm pretty sure there is a ton of information on the ACE and all its morphisms on a Summer Saturday - it was in many ways THE romantic train on the Southern - even more so than the Golden Arrow and Brighton/Bournemough Belles.

Ooops. OK, almost forgot The Night Ferry. Now I bet that was romantic for some, in the more classical sense of the expression On one trip, I certainly (and suddenly) realised the value of learning French stretched to beyond passing 'O' level.

 

[AJM580]

Enjoying this thread. My own recollections of locos like 40s were mainly on Summer Saturday trains out of East Anglia where line speed limits meant they rarely got over 70 mph. I did get 90+ out of 40145 on the Silver Jubilee charter in 2005 when she ran non stop Liverpool St - Norwich in 103 minutes or so.

Generally the Virgin 47/8s could be relied upon for some high speed as well - 47848 at 104/105 across the Somerset levels in 1999 and just before the end of XC loco-hauled I clocked 47831 well into three figures down Whiteball.

D9000 was sampled on various Anglia turns during 1999 - 2002 and the most I got out of her then was 103 mph through Witham heading north on load 10 (kept standard 86 timings as well).

 

[70014IronDuke]

I think we forget the characteristics of the locos that preceded diesels and what people were used to. Starting off, steam can be applied at full boiler pressure to the pistons throughout their travel .....

Not exactly an efficient way to use the energy within the steam though.

 

[70014IronDuke]

Some cracking logs there. I think the Westerns were perfectly capable engines but I've read that the transmission wasn't ideally suited to the engines (can't render exactly) and that when well run in they could often struggle to achieve their 90 mph rating.

I don't know about the transmission, but I know some maintenance men did not like them. Lots of compled bits to disassemble and reassemble in very restricted space is what I remember being told.

 

[70014IronDuke]

Here's a photo of 6003 all decked out with Red Dragon Headboards about to back onto the train at Cardiff in 1960

https://books.google.co.uk/books?id=_i_xoXh2tAgC&pg=PA34&lpg=PA34&dq=western+region+king+cardiff+canton&source=bl&ots=t0_GlRr0lt&sig=Bx7-KPdUQq4yg0df4zJHfkVTyG8&hl=en&sa=X&ved=0ahUKEwinw5-Q8PbZAhVDGsAKHWHRAMQQ6AEIajAN#v=onepage&q=western region king cardiff canton&f=false

....

I know that Kings worked on both Cardiff and Bristol turns during their service. And, AFAIK, the Red Dragon (being particularly heavy) was a regular turn in some periods. But you said something about "until displaced by diesels' - meaning c 1962. That was my point - Kings were, IMX, rare west of Reading on the Bristol/Cardiff routes by 1962. Even at Reading in April 62 one Sunday I never saw one.

 

[Millisle]

After my first couple of years in Edinburgh in the late '70s, the Inverness service home went from 2x26s to a 47 normally, but sometimes a 40, which to my recollection did pretty well. On the other hand the one I remember best featured a fail at Sinclairtown, Kirkcaldy, just by the then Nairn's now Forbo linoleum works. The engine could not maintain vacuum and the train repeatedly got to 2mph and ground to a halt. After a long delay a 20 was found and the train including the 40 to Perth at something distinctly superior than walking pace.
I do recall one other 40 fail, at Agecroft Jcn, on the Victoria portion of a Glasgow/Edinburgh splitter. After I had spent a good while hanging out of the window trying to see what was going on, the guard came past and I asked what the deal was and he said with a chuckle, 'The engine's old and tired, like me.'

 

[hexagon789]

After my first couple of years in Edinburgh in the late '70s, the Inverness service home went from 2x26s to a 47 normally, but sometimes a 40, which to my recollection did pretty well. On the other hand the one I remember best featured a fail at Sinclairtown, Kirkcaldy, just by the then Nairn's now Forbo linoleum works. The engine could not maintain vacuum and the train repeatedly got to 2mph and ground to a halt. After a long delay a 20 was found and the train including the 40 to Perth at something distinctly superior than walking pace.
I do recall one other 40 fail, at Agecroft Jcn, on the Victoria portion of a Glasgow/Edinburgh splitter. After I had spent a good while hanging out of the window trying to see what was going on, the guard came past and I asked what the deal was and he said with a chuckle, 'The engine's old and tired, like me.'

A 40 would've been fine on the Scottish internal routes, other than the stiff gradients there was a 75 mph ceiling in place until about the early 80s other than on the Edinburgh and Glasgow which was 90 from 1972.

 

[hexagon789]

I don't know about the transmission, but I know some maintenance men did not like them. Lots of compled bits to disassemble and reassemble in very restricted space is what I remember being told.

I read that the 3-stages of the transmission did not marry well to the torque of the engine or something.

 

[Bevan Price]

I think we forget the characteristics of the locos that preceded diesels and what people were used to. Starting off, steam can be applied at full boiler pressure to the pistons throughout their travel (within the limits of the adhesion), so locos were very good at moving heavy trains at slow speeds. Look at the 9F pulling 2000 Tonnes at the ESR.
I'm always amazed at the huge old freight trains that used to lumber around in the care of one relatively small steam engine. Electric traction motors cannot be used at full power in these circumstances as the lack of back-EMF means they overheat rapidly. Electric transmission is excellent for continuing to supply power when running fast though, which steam is not so good at.
Hence both the apparent disappointment at low initial acceleration of diesels and the delight at the much higher speeds of new traction up and over the tops of banks. And the facts that a) modern passenger trains like Pendolinos are relatively light weight (compared to Mk 1s for example) and b) we don't really expect them to drop to a crawl on Shap or Beattock.

Pendolinos are anything but light - with an average weight of over 50 tons per coach. Early Mark 1s weighed 33 to 34 tons; those with newer bogies weighed about 37 tons. Their high performance comes from having a lot of horse power.

 

[hexagon789]

Pendolinos are anything but light - with an average weight of over 50 tons per coach. Early Mark 1s weighed 33 to 34 tons; those with newer bogies weighed about 37 tons. Their high performance comes from having a lot of horse power.

I'd imagine it's the tilt equipment, traction equipment and motors that make up the balance. The Mk1s are actually quite light by modern standards, the Mk4s weight about 41 tonnes each.

 

[randyrippley]

I thought there were some logs of the Bulleid diesels on the Southern Railway website here

www.semgonline.com/home.html - But I haven't been able to find them.
..................

I think this may be the page you were looking for, but it doesn't give any real performance details
http://extra.southernelectric.org.uk/features/historical-features/watexdieselops.html

 

[randyrippley]

I don't know about the transmission, but I know some maintenance men did not like them. Lots of compled bits to disassemble and reassemble in very restricted space is what I remember being told.

Better way to look at that is engineers trained on steam were trying to work on diesel engines and transmissions with minimal training, shortage of parts, and in converted unsuitable steam sheds. I read somewhere that one of the commonest causes of failure of the early hydraulics was steam engine soot in the transmission fluid due to an inability to maintain cleanliness standards

Didn't help of course that it seems whoever translated the german manuals got the equivalent grade of UK oil wrong, so the transmissions wore prematurely

 

[hexagon789]

Better way to look at that is engineers trained on steam were trying to work on diesel engines and transmissions with minimal training, shortage of parts, and in converted unsuitable steam sheds. I read somewhere that one of the commonest causes of failure of the early hydraulics was steam engine soot in the transmission fluid due to an inability to maintain cleanliness standards

I think similar issues happened with certain locos traction motors.

 

[Cowley]

I've dug out some more logs as they may be of interest, but I'll make these the last for now because I'm worried it'll be getting just a little bit tedious for some here

Anyway the first features a ton up class 52 from Westbury to Paddington, not a bad effort for 90 mph. locomotive, and the second details four Western runs between Taunton and Exeter, definitely showing their superiority over a class 47 at Whiteball I think? The last two show just how capable the Hymek Class 35s were in their time, I imagine a class 40 would struggle to match that performance on the Newton Abbot to Paddington excursion working, loaded with thirteen bogies?

Some really interesting stuff there Mr Bridge (and I don’t think any of us are finding it tedious). 102mph through Southall must have been pretty incredible behind D1068 on that run. Just goes to show what a Western was capable of.
I remember how impressive D1015 on 14 was taking on the banks west of Taunton a few years ago. I’d been up those hills behind many different classes over the years, yet D1015 had something different about the way it dug in on Hemerdon with purpose (even with a massive load), and you just knew it was going to cope with it no matter what the load... Incredible machines.

The logs from the Hymeks show also how capable they were. They really were competent machines even on loads that were far heavier than we’d hook behind even a type 5 now... Going on the logs, yet again they were no slouches in getting a heavy train away from a start.
Fascinating stuff.

 

[AndrewE]

Not exactly an efficient way to use the energy within the steam though.

Agreed, but if it's maximum tractive effort you are looking for, then that is about as much force as can be exerted. I was ignoring cut-off etc to make the point that starting from rest or as speed drops you can theoretically blow the piston all the way in both directions. I acknowledge that adhesion is a major limiting factor, but that applies to electric transmission too. If you keep full power applied to an electric motor as the speed drops then it will rapidly overheat (a DC one anyway.)
When a diesel-electric or an electric train is rapidly losing speed on a gradient you wonder whether it will actually make it, whereas I get the impression that steam got to a balancing point where it just slogged steadily on (adhesion permitting, of course.
Maybe diesel-hydraulic is better than d-e in low-speed or acceleration situations.

 

[Cowley]

I think diesel hydraulics were good from a standing start hence their success on Foster Yeoman stone trains.
Was it also to do with the fact that the bogies were C-C (coupled wheelsets on each bogie?) rather than Co-Co?

 

[hexagon789]

I think diesel hydraulics were good from a standing start hence their success on Foster Yeoman stone trains.
Was it also to do with the fact that the bogies were C-C (coupled wheelsets on each bogie?) rather than Co-Co?

I'm not sure how they compare from a standing start but they are less efficient. While you can get about 81% of the engine power of a Diesel-Electric for traction the comparative figure for a Diesel-Hydraulic is only 65%.

 

[randyrippley]

I'm not sure how they compare from a standing start but they are less efficient. While you can get about 81% of the engine power of a Diesel-Electric for traction the comparative figure for a Diesel-Hydraulic is only 65%.

Where does that figure come from?
In his book, Brian Reed seems to think the efficiencies are about the same - but doesn't give any actual values

 

[edwin_m]

When a diesel-electric or an electric train is rapidly losing speed on a gradient you wonder whether it will actually make it, whereas I get the impression that steam got to a balancing point where it just slogged steadily on (adhesion permitting, of course.
Maybe diesel-hydraulic is better than d-e in low-speed or acceleration situations.

The driver will be watching the ammeters and will reduce power if the current gets too high. If the gradient is beyond the capability of the loco then it will stall, but that's a train that should never have been sent out in the first place. If the gradient is beyond the capability of a steam loco then it will probably reach the limit of adhesion and spin the wheels. Steam locos have the added variable of boiler pressure, reducing tractive effort if it is steaming poorly or has been worked hard earlier, so it's much harder to make a firm prediction of the maximum load on a particular gradient.

 

[AndrewE]

We're not talking about thermal efficiency here, nor the manpower needs or relative manpower or preparation times of the different technologies, which are all well-recognised. "Slow and lumbering" is only about acceleration or top speed, and edwin-m is agreeing that a loco with electric transmission has to be notched back as the speed falls, handicapping it on a n adverse gradient. My experience on steam footplates is that if the fireman is on top of the job the harder it works the more steam it raises.
Cowley, were the diesel-hydraulics physically C-Cs, , i.e geared to lock the axles in synch, or did the oil go through each "traction motor" in series? I'll have to go and do some digging!

 

[Cowley]

Yeah I’m not sure Andrew and I haven’t got much time today, but it would be good to know if you get a chance.

 

[AndrewE]

I've just had a break from other duties, so here it is!
http://www.westernchampion.co.uk/loco-d1015-technical.php has a nice cut-away drawing and says

In this gearbox a combination of bevel and wheel gears transmit the drive downwards. From there cardan shafts (8) transmit the drive to the axle mounted final drive gearboxes

 

[Taunton]

I know that Kings worked on both Cardiff and Bristol turns during their service. And, AFAIK, the Red Dragon (being particularly heavy) was a regular turn in some periods. But you said something about "until displaced by diesels' - meaning c 1962. That was my point - Kings were, IMX, rare west of Reading on the Bristol/Cardiff routes by 1962. Even at Reading in April 62 one Sunday I never saw one.

Yes, by 1962 the Kings had lost their regular work on the WofE and Bristol routes to Warships, although they still substituted from time to time. Their main remaining work was on the Wolverhampton trains, but some were transferred to the Cardiff trains, on which they had been pretty unusual before about 1960. I think they may not have been allowed west of Cardiff, and Landore was the principal shed on the route - note how in the linked photo the King at Cardiff is taking over from an equally headboarded (but much more grimy) Hall, which has brought the train from Swansea. Most services of course were still run with Castles. The Hymeks D7024-39 which took over were delivered between March and June 1962. You maybe missed Kings on the service by weeks.

For some reason the South Wales expresses, which always had the heaviest loads of all services out of Paddington, never seemed to be top priority for power. Back in GWR days, when there were KIngs and Castles, although not in huge profusion, the South Wales expresses were still regular work for Saints - if you don't know what those are, they are effectively a Churchward-era 2-cylinder Hall with larger Castle-sized driving wheels for express service. But not as powerful as a 4-cylinder Castle.

When you think the Hymeks had just ONE of the two engines installed in a Western, although tweaked up with more substantial intercoolers and turbochargers (and they sounded completely different), their performance on heavy work was very creditable. They were equally happy on heavy unfitted coal trains, or shunting a few wagons back and forth in the rickety sidings at the end of the Minehead branch. Really the Western's own equivalent of the Class 33 that served the Southern (and eventually others) so well for so long. Both were built by manufacturers that had gone out of business, so the excuses from Marylebone Road about needing to withdraw them (non-standard, no manufacturer spares, etc) ring hollow. You can imagine what the WR thought of being told that the replacing well-worn Class 31s were their equivalent ...

Incidentally, the Hymeks were a wholly British-built product. The Maybach-concept engines were actually redesigned and made by Bristol Siddeley in Coventry, and the Mekydro transmissions were built by J Stone in Deptford

 

[chorleyjeff]

I think we forget the characteristics of the locos that preceded diesels and what people were used to. Starting off, steam can be applied at full boiler pressure to the pistons throughout their travel (within the limits of the adhesion), so locos were very good at moving heavy trains at slow speeds. Look at the 9F pulling 2000 Tonnes at the ESR.
I'm always amazed at the huge old freight trains that used to lumber around in the care of one relatively small steam engine. Electric traction motors cannot be used at full power in these circumstances as the lack of back-EMF means they overheat rapidly. Electric transmission is excellent for continuing to supply power when running fast though, which steam is not so good at.
Hence both the apparent disappointment at low initial acceleration of diesels and the delight at the much higher speeds of new traction up and over the tops of banks. And the facts that a) modern passenger trains like Pendolinos are relatively light weight (compared to Mk 1s for example) and b) we don't really expect them to drop to a crawl on Shap or Beattock.

My observation at the end of the then platform 6 at Preston in WCML class 40 days was that class 40s were noticeably quicker off the mark with heavy passenger trains than 8P pacifics. This was consistent with the information I understood that steam engines were better at high speed until valve events choked the steam flow. I think it can be misleading to be selective in choosing occasional high performance steam runs rather than day to day normal steam running with class 40 runs - but nevertheless interesting.

 

[Ash Bridge]

A little story relating to class 35 Hymeks. I never forgot the tale told to a friend and myself from the driver whilst being allowed to visit the cab of a Hymek at Bristol TM way back in 1973. He mentioned that the powerful low frequency throb of the BS/Maybach engine when left idling generated no end of complaints from residents living nearby and some not so near to the depot that maintained them, I think he specifically referred to Cardiff Canton. On one occasion when an extremely irate women turned up at the depot foremans office complaining about an engine so noisy that it made cherished ornaments in her property vibrate so much that they had fallen off a shelf or cabinet and dropped to the floor and smashed! An investigation proved that a Hymek was the most likely culprit.

 

[hexagon789]

Yes, by 1962 the Kings had lost their regular work on the WofE and Bristol routes to Warships, although they still substituted from time to time. Their main remaining work was on the Wolverhampton trains, but some were transferred to the Cardiff trains, on which they had been pretty unusual before about 1960. I think they may not have been allowed west of Cardiff, and Landore was the principal shed on the route - note how in the linked photo the King at Cardiff is taking over from an equally headboarded (but much more grimy) Hall, which has brought the train from Swansea. Most services of course were still run with Castles. The Hymeks D7024-39 which took over were delivered between March and June 1962. You maybe missed Kings on the service by weeks.

For some reason the South Wales expresses, which always had the heaviest loads of all services out of Paddington, never seemed to be top priority for power. Back in GWR days, when there were KIngs and Castles, although not in huge profusion, the South Wales expresses were still regular work for Saints - if you don't know what those are, they are effectively a Churchward-era 2-cylinder Hall with larger Castle-sized driving wheels for express service. But not as powerful as a 4-cylinder Castle.

When you think the Hymeks had just ONE of the two engines installed in a Western, although tweaked up with more substantial intercoolers and turbochargers (and they sounded completely different), their performance on heavy work was very creditable. They were equally happy on heavy unfitted coal trains, or shunting a few wagons back and forth in the rickety sidings at the end of the Minehead branch. Really the Western's own equivalent of the Class 33 that served the Southern (and eventually others) so well for so long. Both were built by manufacturers that had gone out of business, so the excuses from Marylebone Road about needing to withdraw them (non-standard, no manufacturer spares, etc) ring hollow. You can imagine what the WR thought of being told that the replacing well-worn Class 31s were their equivalent ...

Incidentally, the Hymeks were a wholly British-built product. The Maybach-concept engines were actually redesigned and made by Bristol Siddeley in Coventry, and the Mekydro transmissions were built by J Stone in Deptford

I've read of some impressive runs with some pretty heavy loads that would've taxed similarly power locos, but the Hynes seemed to manage no bother. I seem to also recall reading that their transmissions were "tuned" to suit the engines better than the Westerns were.

 

[edwin_m]

We're not talking about thermal efficiency here, nor the manpower needs or relative manpower or preparation times of the different technologies, which are all well-recognised. "Slow and lumbering" is only about acceleration or top speed, and edwin-m is agreeing that a loco with electric transmission has to be notched back as the speed falls, handicapping it on a n adverse gradient. My experience on steam footplates is that if the fireman is on top of the job the harder it works the more steam it raises.
Cowley, were the diesel-hydraulics physically C-Cs, , i.e geared to lock the axles in synch, or did the oil go through each "traction motor" in series? I'll have to go and do some digging!

I said that power has to be notched back as speed falls but I don't agree with your contention that a steam loco is automatically better on gradients.

Gradient climbing at low speeds depends entirely on tractive effort - power doesn't come into it at all. And the tractive effort depends on design-specific factors such as the amount of weight on the powered axles, wheel size and gearing, as well as more transient factors notably available adhesion and boiler pressure. Steam locos tended to be designed for a particular duty, whereas the early diesel and electric classes were intended for mixed traffic use, so it may be that a steam loco build for low-speed freight duties would have more tractive effort than a jack-of-all-trades diesel and therefore a greater ability to slog up a gradient.

However making the same comparison at higher speeds, the difference in power becomes more important. A diesel may and an electric almost certainly does have more power than a steam loco of a similar size, which allows a gradient to be climbed at higher speed and makes it less likelly the speed will drop off to the extent that power has to be reduced. The steam loco also has the useful ability to boost its power for a short period by running down the pressure in the boiler, at the cost of lower performance later on as pressure is recovered. An electric can do something similar because the equipment is able to draw more power for short periods before it gets too hot, but a diesel can't because available power is limited by the rating of the engine.

 

[whitrope69]

I once read an interesting slant on locomotive performance called "The Singer not the Song" the gist of the story was in the diesel days it was the man in the seat who more often than not determined if a run was poor, average or sparkling. With Deltic locomotives on the ECML my experience was some drivers always ran at speeds over 100mph, others when conditions out on the road required it and finally there was a small minority who couldn't be tempted near 100mph whatever the conditions on the day.

 

[hexagon789]

I once read an interesting slant on locomotive performance called "The Singer not the Song" the gist of the story was in the diesel days it was the man in the seat who more often than not determined if a run was poor, average or sparkling. With Deltic locomotives on the ECML my experience was some drivers always ran at speeds over 100mph, others when conditions out on the road required it and finally there was a small minority who couldn't be tempted near 100mph whatever the conditions on the day.

Bit like braking, until the defensive driving restrictions came in you'd have drivers who came in fast using full service braking and others who braked light and early.

 

[The Crab]

I said that power has to be notched back as speed falls but I don't agree with your contention that a steam loco is automatically better on gradients.

Gradient climbing at low speeds depends entirely on tractive effort - power doesn't come into it at all. And the tractive effort depends on design-specific factors such as the amount of weight on the powered axles, wheel size and gearing, as well as more transient factors notably available adhesion and boiler pressure. Steam locos tended to be designed for a particular duty, whereas the early diesel and electric classes were intended for mixed traffic use, so it may be that a steam loco build for low-speed freight duties would have more tractive effort than a jack-of-all-trades diesel and therefore a greater ability to slog up a gradient.

However making the same comparison at higher speeds, the difference in power becomes more important. A diesel may and an electric almost certainly does have more power than a steam loco of a similar size, which allows a gradient to be climbed at higher speed and makes it less likelly the speed will drop off to the extent that power has to be reduced. The steam loco also has the useful ability to boost its power for a short period by running down the pressure in the boiler, at the cost of lower performance later on as pressure is recovered. An electric can do something similar because the equipment is able to draw more power for short periods before it gets too hot, but a diesel can't because available power is limited by the rating of the engine.

I think it was running down the level of water ("mortgaging" the boiler) in order to keep the pressure up for a short period.