Webb Designs - Successes and failures

[webbfan]

Moderator note: Posts #1 - #4 originally in this thread:

Trivia: Train types where significant withdrawals took place before the last ones were built

I find myself thinking of the 9Fs, with their scandalously short life - were any/many withdrawn before the 1961 completion of 92220?

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According to E.L. Ahrons in "The British Steam Locomotive, 1825 to 1925" he suggests that whilst the Webb LNWR "compound" locomotives could (sometimes) give good performances, they were also seriously flawed. Whilst some visually looked like a 2-4-0 wheel arrangement, in fact the two driving axles were not connected, and rotated independently - making the true wheel arrangement 2-2-2-0.

Ahrons reported that they often had problems starting, and on occasions they could give the odd situation that the front axle was trying to move forwards, but the rear axle was trying to move backwards. With a desire to increase train loads from the early 1900s, it is perhaps not surprising that Whale chose to get rid of "troublesome" locos -- although perhaps too hastily, leading to shortages of locos mentioned above.

Some other locos with shortish lives were some express types with a single driving wheel (2-2-2 or 4-2-2), e.g. on GNR, GWR and MR. Whilst many were competent at moving light loads quite quickly, they also could not cater well for heavier trains - and were superseded by 4-4-0, 4-4-2 or 4-6-0 designs.

Well thats a short statement about a complex subject covering 10 or more classes of engines. They ranged from one of the best engines of the day (Teutonics) to some with curious features - such as boilers with central combustion chamber that probably did nothing except collect ash and block a few tubes. Yes Webb claimed there was reduced friction by not having coupling rods, but some suggest there wasn't room for them However later classes were coupled. Personally recon the jury is still out on how good they were - one of the few balenced articles appeared in Backtrack a while ago - written by M Rutherford. Suggest everyone should read that before commenting
Yes the opposing axles was a good story but myth or regular occurrence ? Suggest not proven
Suspect Whale was out of his depth to start off with, he was a running man and not a design or production engineer, perhaps chosen as someone that could be controlled. Unfortunately perhaps influenced by the wrong people. There is the question that if he wasn't impressed by Webb Compounds then why did he allow the building of Bill Baileys to go ahead. That may be a unfairly maligned class.

 

[Bevan Price]

Well thats a short statement about a complex subject covering 10 or more classes of engines. They ranged from one of the best engines of the day (Teutonics) to some with curious features - such as boilers with central combustion chamber that probably did nothing except collect ash and block a few tubes. Yes Webb claimed there was reduced friction by not having coupling rods, but some suggest there wasn't room for them However later classes were coupled. Personally recon the jury is still out on how good they were - one of the few balenced articles appeared in Backtrack a while ago - written by M Rutherford. Suggest everyone should read that before commenting
Yes the opposing axles was a good story but myth or regular occurrence ? Suggest not proven
Suspect Whale was out of his depth to start off with, he was a running man and not a design or production engineer, perhaps chosen as someone that could be controlled. Unfortunately perhaps influenced by the wrong people. There is the question that if he wasn't impressed by Webb Compounds then why did he allow the building of Bill Baileys to go ahead. That may be a unfairly maligned class.

I was trying to extract a summary from quite lengthy comments by Ahrons, so could not cover everything he wrote. The opposing axles story was apparently true, and occurred more than once - to summarise, it could arise due to differences in behaviour of the high pressure & low pressure cylinders.

True - Webb did also make some good engines, notably the long-lived (after rebuilds) freight 0-8-0s, and some long-lasting 0-6-0s and passenger tank locos.

As for Whale - and many other chief engineers, the actual design work was often performed by drawing / design offices, and I suspect that in a few cases, the only tasks performed by the chief engineer may have been tell the design office what was needed, and then to sign approval of the drawings....

As an aside, the entire book is worth reading for anyone interested in the history of steam locos. Although not everybody will agree with some of his comments, Ahrons was a sort of precursor to Cecil J Allan and O S Nock, as a student of locomotive performance.

 

[etr221]

While Francis Webb has - looking back - what can be best described as something of a mixed reputation, the directors of the LNWR (who I don't think were fools) reckoned he was worth £7000 per year - converted to modern figures best part of a million. How many railway officers - of any role, anywhere - have ever been on anything like that?

 

[webbfan]

While Francis Webb has - looking back - what can be best described as something of a mixed reputation, the directors of the LNWR (who I don't think were fools) reckoned he was worth £7000 per year - converted to modern figures best part of a million. How many railway officers - of any role, anywhere - have ever been on anything like that?

It was the so-called parsimonious Moon that gave him the large salary - actually Moon was willing to spend money as long as it benefited the shareholders. Webb certainly gave the railway what it wanted - manufacturing that was amongst the best in the country, locomotives that were cheap to build and did the job asked of them. Its often forgotten that Crewe built over 3000 locomotives during the period when Webb was CME and only 300 or so were compounds - and the debate over how many were good and how many duds (and was it the engines or drivers) will go on for a while yet, but at least it is becoming more balanced.

Some CME's were heavily involved in design Gresley for one, Webb certainly was - he was the chief draughtsman for Ramsbottom so was able to design some locomotives and later improve them with rebuilds - hence improved precedents etc. He was also a production engineer, took Ramsbottoms excellent start and made Crewe into ....

Not everyone believes the opposing axle story - another one for debate. Think have only seen one description by a reliable observer. Everyone else appears to repeat the story but do not quote sources. That doesn't mean it never happened. Well known LNWR modeller Roger Stapleton built a 4mm Teutonic (i think) kit with the ability to not run with opposing axles.

 

[Bevan Price]

It was the so-called parsimonious Moon that gave him the large salary - actually Moon was willing to spend money as long as it benefited the shareholders. Webb certainly gave the railway what it wanted - manufacturing that was amongst the best in the country, locomotives that were cheap to build and did the job asked of them. Its often forgotten that Crewe built over 3000 locomotives during the period when Webb was CME and only 300 or so were compounds - and the debate over how many were good and how many duds (and was it the engines or drivers) will go on for a while yet, but at least it is becoming more balanced.

Some CME's were heavily involved in design Gresley for one, Webb certainly was - he was the chief draughtsman for Ramsbottom so was able to design some locomotives and later improve them with rebuilds - hence improved precedents etc. He was also a production engineer, took Ramsbottoms excellent start and made Crewe into ....

Not everyone believes the opposing axle story - another one for debate. Think have only seen one description by a reliable observer. Everyone else appears to repeat the story but do not quote sources. That doesn't mean it never happened. Well known LNWR modeller Roger Stapleton built a 4mm Teutonic (i think) kit with the ability to not run with opposing axles.

I doubt that Ahrons would have quoted the opposing axles "events" unless he believed that they happened.
E.L. Ahrons (1866-1926) trained as a draughtsman at Swindon (under W. Dean), and later attained senior engineering draughtsman posts in industry, including at loco builders Beyer Peacock; he also held Government posts during WW1.

 

[Gostav]

I was trying to extract a summary from quite lengthy comments by Ahrons, so could not cover everything he wrote. The opposing axles story was apparently true, and occurred more than once - to summarise, it could arise due to differences in behaviour of the high pressure & low pressure cylinders.

True - Webb did also make some good engines, notably the long-lived (after rebuilds) freight 0-8-0s, and some long-lasting 0-6-0s and passenger tank locos.

As for Whale - and many other chief engineers, the actual design work was often performed by drawing / design offices, and I suspect that in a few cases, the only tasks performed by the chief engineer may have been tell the design office what was needed, and then to sign approval of the drawings....

As an aside, the entire book is worth reading for anyone interested in the history of steam locos. Although not everybody will agree with some of his comments, Ahrons was a sort of precursor to Cecil J Allan and O S Nock, as a student of locomotive performance.

I have a question for a long time: why not use rods to coupling the front and rear wheels?

 

[webbfan]

I doubt that Ahrons would have quoted the opposing axles "events" unless he believed that they happened.

Perhaps, but am not suggesting he didn't nor that the event didnt occur, however there are very few reports by individuals that did see it. So question becomes how frequent an occurrence was it. The story morphed into there were men available at every station with pinch bars to move the engine (and train) forward.
Same with a short paragraph on Webb compounds, care has to be taken as too often see people read the sentance they want to see and write that all Webb engines were useless.

I have a question for a long time: why not use a rod to coupling the front and rear wheels?
Webb claimed it was to reduce friction thus enhance performance ! Few were convinced. Think it was Tuplin that suggested there wasn't room for rods. Was only 3 cylinder compounds run like this.

 

[etr221]

I have a question for a long time: why not use a rod to coupling the front and rear wheels?
Webb claimed it was to reduce friction thus enhance performance ! Few were convinced. Think it was Tuplin that suggested there wasn't room for rods. Was only 3 cylinder compounds run like this.

Dugald Drummond (of the LSWR) produced half a dozen 4 cylinder simple 'double single' 4-2-2-0s (T7 and E10 classes), which all lasted into SR days.

Webb's 4 cylinder compound passenger locos (on the LNWR) were coupled - 4-4-0s (many later rebuilt as 2 cyl simples).

 

[Bevan Price]

Perhaps, but am not suggesting he didn't nor that the event didnt occur, however there are very few reports by individuals that did see it. So question becomes how frequent an occurrence was it. The story morphed into there were men available at every station with pinch bars to move the engine (and train) forward.
Same with a short paragraph on Webb compounds, care has to be taken as too often see people read the sentence they want to see and write that all Webb engines were useless.

According to Ahrons, difficulty in starting was a common problem, especially with the otherwise good Teutonic Class -- but a separate matter from the contra-rotating axles.
What apparently happened was again a problem with the compounding system. There were 2 high pressure cylinders and 1 low pressure cylinder. Sometimes, you could get circumstances with one high pressure cylinder open to steam, but if the loco had stopped "dead centre" (valve gear, I assume), there was little steam in the second high pressure cylinder, and the ports to the low pressure cylinder were closed. In those circumstances, there was insufficient power to get the train moving. Once you got the train moving, everything started to function normally. A modification using a by-pass valve is said to have partly solved the problem, but Ahrons said the class always remained prone to starting problems.

For anyone interested, the Ahrons book mentioned earlier includes a whole 20 page chapter devoted to compound locos, about half of which is devoted to the Webb compounds.

2nd hand reprints can be obtained for as little as £15 - beware of offers at around £50 - that seems a bit excessive to me.

e.g.

Item no longer available

The item you are looking for is no longer available. <br/>

www.abebooks.co.uk

 

[webbfan]

Yes there were problems with starting with all Webb compounds and he never really solved that. But perhaps the biggest problem was the ratio of volumes between the low and high pressure cylinders. The theoretic best value wasn't known at the time, Webb started off fairly close but moved away as classes evolved. Meant the low pressure cylinder(s) were not doing much so in effect they could be close to small 2 cylinder engine.
Alfred the Greats were rebuilt under Whale - but signed off by Webb - to Benbows. They had an extra set of valve gear so could have different cutoffs for high and low pressure cylinders - said to improve their performance. The other 4-cylinder engines (Jubilees) as said above were converted to 2 cylinder simples and given Alfred the Great boilers - Renown class, effectively a small Precursor !

 

[Taunton]

Tuplin also gave a detailed explanation of why the wheels could initially revolve in opposite directions.

I suspect the continuing fascination with compounding, in the end a dead end, came from engineers who in their younger days had done time at sea, as it seems a notable number had done. Reciprocating steamships were invariably compound, sometimes triple or even quadruple expansion. Of course, a ship is the opposite to a locomotive, plenty of space and no restriction on weight, but unable to take on water between ports (no, boilers do not use seawater !), so the need to be really economical with that.

 

[BayPaul]

Tuplin also gave a detailed explanation of why the wheels could initially revolve in opposite directions.

I suspect the continuing fascination with compounding, in the end a dead end, came from engineers who in their younger days had done time at sea, as it seems a notable number had done. Reciprocating steamships were invariably compound, sometimes triple or even quadruple expansion. Of course, a ship is the opposite to a locomotive, plenty of space and no restriction on weight, but unable to take on water between ports (no, boilers do not use seawater !), so the need to be really economical with that.

By the time triple expansion came along, most (all?) steamships would have had a condenser, so water use wasn't a major factor. Reducing engine size on a ship is always a good thing, as it increases cargo capacity. I'm not an expert, but I always understood that compound engines simply used less coal - and since it all has to be carried a long way (and shovelled into the boilers), there is a great advantage to reducing coal consumption on a ship as it increases cargo capacity and reduces manning.

 

[etr221]

The issue with compounding on railway locomotives was whether the benefits - which there undoubtedly were - were worth the increased complexity, and consequent necessary upskilling of drivers, to get the best out of it. The French believed they were...

A comment I have seen on Webb's compounds was that the firemen loved them, for their low coal consumption, and the drivers hated them, as they really had to know to drive them.

 

[webbfan]

Exactly the point. Compounds could extract more energy from steam therefore require less coal. Webb was very aware of the value of saving coal as not long after he became CME (equivalent) the cost of coal rose to almost double its earlier cost.
If the extra expense of compounding - capital and maintenance - was exceeded by the saving on coal and the engines were able to keep time on the allocated jobs then it was worth pursuing. Webb should be congratulated for attempting to reduce costs this way as well as for how successful he was. There were successes and there were questionable results, but at least he made a magnificent effort.

He even tried a triplex but it was only just capable of moving itself so quietly parked

Didn't realise any loco engineers started in marine environment - do you have any names of notable/influential persons.

As an aside an American railroad purchased and trialled one of the Webb compounds although built by Beyer Peacock. Wasn't considered a success for them.

 

[matchmaker]

A quote from "London Midland & Scottish - a railway in retrospect" by Hamilton Ellis.

"Mrs Royle, as a little girl, had been turned over and spanked after a tea party at the Chief Mechanical Engineer's house in Crewe, for innocently asking Francis Webb why his new engines sometimes turned their four big wheels in opposing directions at starting."