How common were outside cylindered 0-6-0 tender engines?

[NZRedBaron]

"Hey folks, Tex of the Black Pants Legi-"

 

*cough*

 

Sorry about that, couldn't resist the compulsion. Anyway though, I was looking at some old Electrotren 0-6-0T's on Hattons and elsewhere, and I had a sudden thought; were there any British-operated, or British-built 0-6-0 tender engines with outside cylinders? If there were, what were they, and how many of them had been built?

 

Thanks.

[Buhar]

They were certainly not common in Britain. I can only think of one off the top of my head, the one-off North Staffs 4 cylinder that was rebuilt from an 0-6-0T and had a very short life. Others will no doubt emerge.

Alan 

[Joseph_Pestell]

Interesting question.

 

Could it be an issue of gauge that makes it difficult to find space for outside cylinders? Placing them outside the wheelbase of the loco might make it unstable at speed.

[Dave John]

Some early ones on the Caledonian. Class 96 built 1849 but converted to 0-4-2. Class 188 built 1858, class 120 built 1872, class 631 built 1874.  Some of the 631 class lasted through the Edwardian era.

 

A comprehensive  study can be found in 

 

https://www.crassoc.org.uk/web/node/284

 

 

[eastglosmog]

Derwent (1845) of the Stockton and Darlington was outside cylindered, though not in the usual configuration:

https://preservedbritishsteamlocomotives.com/25-derwent-0-6-0-stockton-darlington-railway/

[The Stationmaster]

Apart from access to the valve gear there were very good reasons for keeping to inside cylinders on 0-6-0s unless they had a long wheelbase.  Outside cylinders move the thrust of the pistons further away from the centre line of the engine which can cause oscillation and increase ear in numerous parts of the engine including stress on the franes and axleboxes.  

 

So British designers tended to steer away from outside cylinders on 0-6-0s and accept the valve gear inaccessibility as patrt of teh price they had to pay but as labour was cheap in many respects that price was reduced.  And look what happened when they did use the arrangement on a short wheelbase engine where the Western 15XX 0-6-0Ts were very prone to oscillation unless they had a heavy load behind them to steady them.

[Compound2632]

If you look at outside-cylindered 2-2-2s and 2-4-0s, which were a bit more common up to about the 1870s, the nature of the problem becomes apparent:

 

 

[Embedded link to GER Society website]

 

Even with the smaller carrying wheels, the engine is nose-heavy - there's a lot of mass forward of the leading axle and as @The Stationmaster says, that mass distribution is oscillating, which will cause the whole engine to waggle.

 

I think the reason outside cylinders were preferred by some mid-19th century engineers is that this avoided cranked driving axles, which were a problem to manufacture reliably - breakages were a significant problem So once manufacturing techniques had advanced to the point at which crank axle breakages were very rare, inside cylinders were preferred, as giving greater stability, and also, I think, as the cylinder casting could be better supported between the frames.

 

Once leading bogies started being adopted, outside cylinders came back into vogue with some engineers, as the bogie could better support the front-end weight and its side-control reduced the tendency to oscillation - e.g. Stirling's Great Northern 4-2-2s and Adams' LSWR 4-4-0s (and their precursors the Tilbury 4-4-2Ts). I think the attraction was more space between the frames for the valve gear eccentrics and room for bigger valve chests, giving freer circulation of steam and consequently a free-running and faster engine.

 

The obvious parallel development for goods engines would be the 2-6-0 mogul, with which Baldwins had great success in the US. But for the conditions of operation of British goods trains (loose coupled, grease axleboxes, low speed) the benefits of both the freer steam circuit and the stabilising effect of the leading truck would be wasted.

 

In France, on the other hand, long front overhang with outside cylinder was the 19th century norm. Why the difference?

 

 

Edited June 9, 2023 by Compound2632
typo.

[asmay2002]

3 hours ago, Compound2632 said:

In France, on the other hand, long front overhang with outside cylinder was the 19th century norm. Why the difference?

Speeds were lower in France.

[Compound2632]

17 minutes ago, asmay2002 said:

Speeds were lower in France.

 

There was, I understand, for many years a 120 kph (75 mph) speed limit - a law of Napoleon III, so dating from before 1870. This, I gather, is why 20th century French express passenger engines were designed to run at a constant speed uphill and down, and coupled with the long runs between Paris and the major provincial cities, made compounding so attractive. But 75 mph was as exceptional a speed in 1860s France as it was in 1860s Britain. Charles Rous Marten reported to the New Zealand Government in, I think, 1875, that 75 mph appeared to be the practical maximum speed; this was before the adoption of steel rails and tyres. For many years, 40 mph average speed was the norm for express passenger trains on the LNWR, and not much higher elsewhere. Such schedules could be maintained comfortably without running above about 55 mph at any point. I believe it was the case that in France, alone of European countries, similar express passenger average speeds were normal. 

 

So I don't think speed was a factor in the 1850 - 1875 period.

Edited June 9, 2023 by Compound2632

[eastglosmog]

There is this thing, the Sturrock Steam tender (and the loco it was attached to):

http://www.douglas-self.com/MUSEUM/LOCOLOCO/steamtender/steamtender.htm

[The Johnster]

Stephenson had some part to play in this as well, as his early (1832?) assertion that locomotives should have six wheels and inside cylinders was highly influential for many years.  Such locos ran steadily, put their power down on to the track well, and appeared in a plethora of inside cylindered 2-2-2, 2-4-0, 0-4-2, and of course 0-6-0 tender engine examples.  Diversions from Stephenson’s form such as Cramptons were successful until the size had to be increased and eventually fell out of favour.   
 

British locomotive design advanced geologically slowly and reluctantly, I think in part because in the first 50 years CMEs were feeling their way, and were expected to provide successful engines while in positions for which competition was savage; even small failures were career-destroying and the wolves were always gathering.  The result was that they stuck with what they knew worked and were unwilling to stick their necks out if they could avoid it. 
 

Contrast Belgium where experiment was almost compulsory…

[The Johnster]

10 minutes ago, eastglosmog said:

There is this thing, the Sturrock Steam tender (and the loco it was attached to):

http://www.douglas-self.com/MUSEUM/LOCOLOCO/steamtender/steamtender.htm

The Sturrock steam tender engines used on the GN were inside cylindered and, IIRC, outside framed on both loco and tender, an early attempt to deal with the Peterborough-Ferme Park heavy mineral trains.  Perhaps it was a memory of them that led Gresley to try a booster on the P2s for the same job 40 years later…

[Michael Hodgson]

Interesting question.  I think ease of maintenance  is what made outside motion become fashionable for new design only after WW2 when there were more staff shortages.

 

Before the war, ease of maintenance  was perhaps seen as less of an issue than other considerations (the workers can just get on with whatever we choose to give them) .  After the war everything had become clapped out, but you can't renew an entire fleet overnight when the national economy has been bankrupted by the war effort - it would be a matter of priorities.  Although mixed traffic and express passenger locos needed replacement, there was perhaps less urgent need for new designs of shunting engines; replacing life-expired boilers was probably good enough for to keep existing general tender 0-6-0s in use a little longer.  And of course as the "modernisation plan" came in, and the greatest percentage savings by dieselisation was probably to be made by the 08s since shunting locos spend a lot of their time idle, and you don't really want to fire up a steam loco just to do a little shunting.  So perhaps the 0-6-0s were just unlucky in not being designed with outside motion in large numbers?  The point about a tendency to waddle would obviously also count against them.

[Compound2632]

1 hour ago, Michael Hodgson said:

Interesting question.  I think ease of maintenance  is what made outside motion become fashionable for new design only after WW2 when there were more staff shortages.

 

Outside motion is a different question to outside cylinders, as any GWR enthusiast can attest. 

 

A 4-6-0 has a sufficiently long wheelbase to dampen the waddle induced by outside cylinders.

[Nick Holliday]

Getting back to the original question, there were several more along the lines of Derwent on the Stockton and Darlington Railway. I made it around thirty five, and many survived into the 1870’s. The S&DR later also built a few more to a more orthodox design, although featuring an unusual connecting rod arrangement. One or two lasted until 1882.

[Flying Pig]

9 hours ago, Compound2632 said:

I think the reason outside cylinders were preferred by some mid-19th century engineers is that this avoided cranked driving axles, which were a problem to manufacture reliably - breakages were a significant problem

 

I believe that is exactly why the Crewe type was developed.

[JimC]

21 hours ago, The Stationmaster said:

.  And look what happened when they did use the arrangement on a short wheelbase engine where the Western 15XX 0-6-0Ts were very prone to oscillation unless they had a heavy load behind them to steady them.

There's also a weight distribution problem. Inside cylinders can overlap the driving wheels, so can be getting on half a wheel diameter nearer the first axle than outside cylinders. Effectively the leading wheel set is forced back and the locomotive becomes front heavy. It's evident when comparing 15xx and 94xx. 

[NZRedBaron]

I was just curious, you see- one idea I have running around my head is that the (fictitious) light railway that I'm planning to create has an unusual 'house style'; due to the fact the light railway has some limited running rights onto the mainline, many of their locomotives are industrial tank engines that have been rebuilt and mated with second-hand tenders from old main line engines, turning them into tender-tank locomotives not unlike the George England locomotives originally built for the Ffestiniog Railway.

[JimC]

Are you aware of the ex Cornwall Mineral Railway tanks converted to Tender engines for the Lynn and Fakenham Railway?
https://rogerfarnworth.com/2019/11/16/the-lynn-and-fakenham-railway-part-1/ 

There's some other links on my blog page about the GWR history of the locomotives. https://www.rmweb.co.uk/blogs/entry/25405-gwr-13921393-class-0-6-0t-ex-cornwall-mineral-railway/

 

Edited June 10, 2023 by JimC

[NZRedBaron]

... Well, I am familiar with them now, yes.

[bbishop]

23 hours ago, Compound2632 said:

Once leading bogies started being adopted, outside cylinders came back into vogue with some engineers, as the bogie could better support the front-end weight and its side-control reduced the tendency to oscillation - e.g. Stirling's Great Northern 4-2-2s and Adams' LSWR 4-4-0s (and their precursors the Tilbury 4-4-2Ts). I think the attraction was more space between the frames for the valve gear eccentrics and room for bigger valve chests, giving freer circulation of steam and consequently a free-running and faster engine.

There is a story regarding the Tilbury and LSWR Radial tanks.  Thomas Whitelegg worked as a draughtsman under Williams Adams at Stratford and I gain an impression that they were good friends.  Adams moved to Nine Elms where initially he developed some merely competent classes.  The LTSR fell out with the GER and recruited Whitelegg as Locomotive Superintendent who, being relatively inexperienced, requested assistance from Adams. The request was agreed by the LSWR Locomotive Committee.  The friends met and the outcome was both the LTSR "1"  class and the LSWR "415" class, the latter being Adams' first excellent product.   Bill.

[D7666]

Might I suggest people are looking far too deeply into this subject.

 

I would apply Occam's Razor in that the simplest explanation is the most likely.

 

The inside cylinder 0-6-0 came about at a period when when that sort of construction was the norm.

 

They proved to be very useful locos. Fit for purpose as they say these days.

 

So all that happened was the operators said "more of the same please". No need to re-invent them with different arrangements.

 

[JimC]

3 hours ago, D7666 said:

I would apply Occam's Razor in that the simplest explanation is the most likely.

Indeed, but what is the simplest explanation? Is it that designers who were innovative with all sorts of other configurations suddenly became conservative when faced with an 0-6-0, or is it that an outside cylinder 0-6-0 may not work very well? Inspired by this discussion I drew up the chassis for the GWR 94xx (inside cylinder) and 15xx (outside cylinder) 0-6-0PT, (on my Blog post about 15xx if interested) and it was very striking how much various heavy components have to move forward relative to the driving wheels.  One thing that struck me while I was drawing it was just how unbalanced the chassis would look without the back half of the cab and the bunker. Now I'm not a locomotive designer, and I'm probably speculating way beyond my actual knowledge of the subject, but it seemed to me that an outside cylinder 0-6-0 would have to be effectively a long boiler type, or close to it, with the firebox largely behind the last driving wheels in order to counterbalance the cylinders.  So the result, I reckon, would be a very short wheelbase, fine shunting the docks at 5mph, but probably not what the PW side would welcome at 30mph on the mainline!

[The Stationmaster]

On 09/06/2023 at 18:00, Michael Hodgson said:

Interesting question.  I think ease of maintenance  is what made outside motion become fashionable for new design only after WW2 when there were more staff shortages.

 

Not so much 'wasw of maintenance' (although it obviously helped but far more importantly simplifying and reduvcing the time needed for preparation - something which could happen at least once, and sometimes a couple ol times, in very working day whereas maintenance occurred at longer intervals.

 

I would say too that shed level maintyenace work on mst engines would be most likely V&P (valves and pistons_ which although it required n motion to be disconnected didn't necessarily mean that it had to be dropped although it would be much easier on an engine with outside valve gear.

 

But the big saving was on prep time and that was carried out by an expensive Grade - Drivers - so savings there would feed back in improved productivity and reduced costs.  Plus also of course the convenience angle as no pit was needed for oiling - hence the 15XX design on the Western.

 

But the big advantage of inside gear - hence one reason for Churchward using it according to Holcroft - was that it allowed larger bearing surfaces on things like eccentrics (in particular) which improved robustness and reliability.  and of course inside Stephenson valvegear is easier to incorporate than putting it outside where the eccentrics have to fit wihin the loading gauge constraints.

[Compound2632]

1 hour ago, The Stationmaster said:

But the big advantage of inside gear - hence one reason for Churchward using it according to Holcroft - was that it allowed larger bearing surfaces on things like eccentrics (in particular) which improved robustness and reliability.  and of course inside Stephenson valvegear is easier to incorporate than putting it outside where the eccentrics have to fit wihin the loading gauge constraints.

 

I don't think S.W. Johnson ever designed an outside-cylinder engine before the Compounds (unless there's some GER or E&G engine I've overlooked) but I did read that he is reported to have said he wished British railways had been built to Irish 5' 3" gauge, as the extra 6½" between the frames would allow greater bearing area for connecting rods and eccentrics. He did have a small batch of 4-4-0s built with Joy gear (1666 Class) which is driven off the connecting rod, saving the need for eccentrics on the driving axle; they wren't very successful but I suspect that was down to poor valve events rather than a fundamental defect of Joy's gear.