Maunsell U Class 2-6-0

[Robin Brasher]

Brian Sharpe has written an excellent book called Southern Steam Revival published this year by Mortons for Heritage Railway. The section on the U class is on pages 63 to 65.  There is a brief history of the class followed by colour pictures of the four preserved examples: 1618 and 1638 at the Bluebell and 31625 and 31806 at the Mid Hants. The two working examples: 1638 in Maunsell lined green and 31806 in BR lined black with the late crest are shown with rakes of coaches in the correct liveries.

[Horsetan]

Seen it. No drawings, though.

[finelines]

What are the flaws in the drawings? Are the drawings in the Russell book flawed?

 

Are we talking about the kind of error that can be corrected by reference to good photos or are they fundamental?

 

Roger

[Bruciethefish]

The Roche drawings were certainly the genesis of numerous dreadfully inaccurate kits, as were many of the Ian Beattie ones..Rather than take any drawing at face value, it's always best to cross-reference with numerous photos, plus try & measure the real thing, if it's still around.

[pete_mcfarlane]

What are the flaws in the drawings? Are the drawings in the Russell book flawed?

 

Are we talking about the kind of error that can be corrected by reference to good photos or are they fundamental?

 

Roger

 

The ones in the Russell book are weight diagrams - a simplified outline of the loco with a few dimensions shown. They do show the differences between the new-builds and the ex-River tanks, and are probably traced down from the original General Arrangement diagrams so are reasonably accurate. It all depends whether you want to build a model based on a weight diagram or not.

[Horsetan]

According to the drawings list from the NRM Search Engine facility, there are a number of drawings applicable to the new-build "U"s, including at least one GA.

[finelines]

I rarely take any drawing at face value. Back in the 1960s Roche drawings were accepted, but Skinleys weren't. Then somebody said Roche drawings were flawed and it has become accepted wisdom, but nobody can ever tell me what the flaws are and in which drawing.

 

When I was producing my D3 kit I discovered the the Maskelyne drawing was faulty, you could see the width over the footplate was wrong by comparing it to a photograph. Tom Lindsay's MRN drawing seemed to be right. Maskelyne's drawing of Abergavenny was equally faulty, in that case it came from the belief that the centre of the chimney, cylinders and front bogies were in line, which the GA shows they're not.

 

All of which prompted me to ask what is actually wrong with the drawing?

 

Roger

[billbedford]

I rarely take any drawing at face value. Back in the 1960s Roche drawings were accepted, but Skinleys weren't. Then somebody said Roche drawings were flawed and it has become accepted wisdom, but nobody can ever tell me what the flaws are and in which drawing.

 

 

 

There is a problem with the Roche B1 drawing. The expansion link is too far back. It should be somewhere near the line of the crank pin at BDC. I seen lots of kits produced with this arrangement. 

 

The bottom line is understanding the difference between primary and secondary sources and discriminating accordingly.

[bécasse]

The real problem is that these, and most other main line, locomotives weren't built to drawings. In the works of the main line companies, drawings were used to design the locos, not build them, and generally drawings never made their way down from the drawing office to the shop floor. The various shop foremen were given instructions, dimensions and material and took it from there. The skilled men on the shop floor in turn followed their foreman's instructions but did the work in their own way. No two locos even of the same class were ever identical twins, even when brand new, there would always be some differences in, for example, riveting patterns.

 

The private builders were different, by the end of the 19th century they had largely moved to building from drawings, and so main line locos outsourced were much more likely to be near-identical twins. Occasionally this resulted in major problems. When the SR contracted North British to build the 'Scotch" Arthurs, NB were provided with a full set of drawings specially produced by Eastleigh to suit NB's production methods and the locos were built meticulously to these drawings. What Eastleigh failed to tell NB was that it was standard Eastleigh practice to never include working tolerances (men on the shop floor at Eastleigh automatically allowed what was required) and so when the locos were delivered every one of them failed on first steaming and had to have working tolerances, notably between cylinders and pistons, laboriously opened out at considerable cost. The SR had become publicity conscience by this time and these problems were hushed up, and, indeed, remain little known, but I assure you that they happened.

 

General arrangement drawings were exactly that, showing how a loco was "generally arranged", were often produced after a class had been built (usual practice at Swindon, I believe), and, because no design work was involved, were often the work of relatively junior draughtsmen, (they couldn't be done by "tracers" because there was nothing to trace). Weight (and other) "diagrams" were usually drawn to a small scale for immediate incorporation in the railway companies' diagram documents, and, since the essential information in them was not the drawing but the weight and dimension figures, were often the work of drawing office apprentices, (it would have been possible to partly trace them from the much larger GAs using a pantograph tracer but I believe that in practice this was rarely, if ever, done).

 

Obviously this is a simplification, especially in respect of experimental work, but it does help to explain why it is so difficult to produce good model drawings.

 

Finally, if I can give one very simple example to illustrate why drawing office and shop floor practice was so different. Consider the floor of a wooden open wagon with transverse planking. The draughtsman has the centre point of his drawing marked, so to draw the floor in plan he sets his dividers at what he believes will be the (scaled) width of the planking to be used, starts at the centre point and marks off the planking both ways from the centre by swinging his dividers along the centre line. Almost certainly, this method will result in a drawing that shows part-width planks at both ends of the wagon floor. Subsequently down on the shop floor, the carpenter has discovered that the planking material supplied isn't quite the same width as that specified by the draughtsman (say 6¼" instead of 6½") but he knows that this is of no importance. The concept of the wagon centre point means nothing to him, so he cuts the first plank to length (i.e. floor width), lays it complete at one end of the wagon and then carries on in the same fashion down the wagon until he gets to the far end. Here, he probably will have to reduce the width of one plank to fit, but it is only one plank, saving work and wastage.

[billbedford]

The real problem is that these, and most other main line, locomotives weren't built to drawings. In the works of the main line companies, drawings were used to design the locos, not build them, and generally drawings never made their way down from the drawing office to the shop floor. The various shop foremen were given instructions, dimensions and material and took it from there. The skilled men on the shop floor in turn followed their foreman's instructions but did the work in their own way. No two locos even of the same class were ever identical twins, even when brand new, there would always be some differences in, for example, riveting patterns.

What is the source of this information? If would be surprising if true in the light of the number of locos found to have motion parts etc from other machines.

 

The private builders were different, by the end of the 19th century they had largely moved to building from drawings, and so main line locos outsourced were much more likely to be near-identical twins. Occasionally this resulted in major problems. When the SR contracted North British to build the 'Scotch" Arthurs, NB were provided with a full set of drawings specially produced by Eastleigh to suit NB's production methods and the locos were built meticulously to these drawings. What Eastleigh failed to tell NB was that it was standard Eastleigh practice to never include working tolerances (men on the shop floor at Eastleigh automatically allowed what was required) and so when the locos were delivered every one of them failed on first steaming and had to have working tolerances, notably between cylinders and pistons, laboriously opened out at considerable cost. The SR had become publicity conscience by this time and these problems were hushed up, and, indeed, remain little known, but I assure you that they happened.

 

This just doesn't sound right, if only because pistons were invariably fitted with piston rings which were sprung to allow for the differential expansion of the cylinder and piston. Changing piston rings its not a laborious operation. And anyway, wouldn't NBL just have telephone/written to the Eastleigh D.O. to ask what tolerances they should be using.

 

Finally, if I can give one very simple example to illustrate why drawing office and shop floor practice was so different. Consider the floor of a wooden open wagon with transverse planking. The draughtsman has the centre point of his drawing marked, so to draw the floor in plan he sets his dividers at what he believes will be the (scaled) width of the planking to be used, starts at the centre point and marks off the planking both ways from the centre by swinging his dividers along the centre line. Almost certainly, this method will result in a drawing that shows part-width planks at both ends of the wagon floor. Subsequently down on the shop floor, the carpenter has discovered that the planking material supplied isn't quite the same width as that specified by the draughtsman (say 6¼" instead of 6½") but he knows that this is of no importance. The concept of the wagon centre point means nothing to him, so he cuts the first plank to length (i.e. floor width), lays it complete at one end of the wagon and then carries on in the same fashion down the wagon until he gets to the far end. Here, he probably will have to reduce the width of one plank to fit, but it is only one plank, saving work and wastage.

 

You have, of course, to be aware of drawing conventions, but I have looked at a number of original wagon drawings and they all show whole numbers of floor planks, i.e. no filler planks at either end. This would make sense as even in the nineteenth century they had thicknessing machines which could produce plank to any size, negating the need for filling pieces in the floor. Perhaps you are getting confused with wagons with steel underframes, which had end rails that were fitted under the end and allowed the ends to be bolted to the headstocks.

[PhilH]

I think the piece about the pistons and cylinders shows how nonsensical parts of that post are.

 

The defects on the Scotch Arthurs were generally considered to be a product of the engines being built to a price, along with general poor workmanship and corner cutting.

 

As far as motion work goes, I have been fortunate enough to work on several Bulleid pacifics over the years. These have included original and rebuilt light pacifics and Merchant Navies. It has constantly amazed me how different parts from various engines have been nailed on to other engines, indeed the rebuilt light pacific I mostly work on now has several motion parts from a couple of MNs.

 

I contend that this would not be possible without complete adherence to design drawings...indeed, one mechanical foreman I worked under who knew most things there are to know about Bulleids asserted that any coupling rod produced for a Bulleid could be fitted onto any other member of the class, so good was the adherence to design.

[pete_mcfarlane]

And if there was a problem with the first loco delivered, you'd be on the telephone to NBL pretty quick to make sure that no more were delivered until the problems were rectified.

[Horsetan]

....and suddenly I realise how inaccuracies in received wisdom get passed on....

[Robin Brasher]

12:02 Sunday 13th December. Maunsell U class 2-6-0 31806 with a Santa Special at Swanage Station. The Devon Belle Observation Car has been hired from the Paignton and Dartmouth steam railway. The green mark 1 coaches are historically correct for a locomotive with the late BR crest.

 

The U class was the 4th most popular item in the recent 2015 00 gauge wish list poll and was the most popular Southern locomotive so I hope someone will make a ready to run version soon.

[Guest]

12:02 Sunday 13th December. Maunsell U class 2-6-0 31806 with a Santa Special at Swanage Station. The Devon Belle Observation Car has been hired from the Paignton and Dartmouth steam railway. The green mark 1 coaches are historically correct for a locomotive with the late BR crest.

 

The U class was the 4th most popular item in the recent 2015 00 gauge wish list poll and was the most popular Southern locomotive so I hope someone will make a ready to run version soon.

There are actually two Pullman Observation cars in preservation: The one pictured, and the one at the Dartmouth Steam Railway. Swanage's example is Car No14 while Dartmouth's is Car No13. No14 entered service at Swanage in 2008 after overhaul into working order following its return from the USA, where it had been based since 1969.

 

Regards,

Matt

[Guest]

Earlier in the thread, it was mentioned that there were 3 main variants of the U Class: K-Rebuild, New Build and U1. However, I think it went unmentioned that some received front-end rebuilds under BR. This included:
New cylinders with outside steam pipes
BR Standard Chimney
New front-frame section

Apparently, the tale-tell way of telling the difference between the two, was the way the frames at the front of the loco were shaped. New-Builds and K-Rebuilds had straight frames running from the smokebox to the buffer-beam, whereas BR Rebuilds had curved frames.

Therefore, it's a pretty split division in preservation with both the Swanage based moguls being BR Rebuilds and the two at the Bluebell being 'New-Builds'

 

Regards,
Matt

[Robin Brasher]

Both the Pullman Observation cars are on the Swanage Railway now. Car 14 is in a siding at Herston and car 13 is being used for the Christmas Belle. Car 13 has a dark grey roof and has got a working bar. The Swanage Railway does not allow drinks on car 14 because the Railway is worried about drinks being spilt on the carpet.

[Guest]

Both the Pullman Observation cars are on the Swanage Railway now. Car 14 is in a siding at Herston and car 13 is being used for the Christmas Belle. Car 13 has a dark grey roof and has got a working bar. The Swanage Railway does not allow drinks on car 14 because the Railway is worried about drinks being spilt on the carpet.

Really? Oops...

Apologies for my jumping the gun there.

Is this the first time the two have been together in preservation? If ever?

[Robin Brasher]

It is probably the first time they have been together in preservation. Car 14 based at Swanage was rescued from America. It went there with the Flying Scotsman and ended up as a café. Someone took a photograph recently of cars 13 and 14 together in a siding at Herston. Car 14 is still there but car 13 is being used for the Christmas Belle.

[bike2steam]

Apologies for my jumping the gun there.

 

 

Don't worry about it, you can't be right all the time ( don't I know it!!), you just keep showing your keen-ness.

[Forester]

I have to say if I were a manufacturer considering producing a U, it would be a U1 just to move further away from the N, which is in common production.

 

The U1 is quite an interesting and a more impressive looking loco in my view.

[Robin Brasher]

In the 2016 wish list 400 people voted for the 00 gauge SR U class 2-6-0 (31610-31639), (31790-31809) making it the second most popular locomotive and the most popular SR locomotive.

 

Only 52 people voted for it in N gauge. It was the ninth most popular locomotive and more people wanted a Q class 0-6-0.

 

The U1 class (31890-31910) did not do so well. In 00 gauge only 192 wanted it and 32 in N gauge.

 

Producing one seems like a minefield.

 

Meanwhile I enclose a picture of 31806 near Corfe Viaduct at 14:42 on Sunday 20th November 2016 with the 14:40 service from Norden to Swanage.

 

Perhaps I will be able to reproduce an 00 gauge version of this scene in the future.

[N15class]

Are there not kits for the U's

[Judge Dread]

Are there not kits for the U's

There was a kit for the U's and U1's and N's and N1's.

I refer to the Wills bodyline kit design to fit on a Tri-ang 2-6-2 tank loco.

I bought such a kit and donated the tender elsewhere and used the body on a Hornby-Dublo chassis to produce a Class W, three cylinder tank loco.

I ran it on my loft layout for  a number of years and then I rewheeled it and converted to EM  for my exhibition layout Brockley Green SE4 layout.  Although that layout has gone south, I retained the loco and one day I may convert it to 00 and run it on my present exhibition layout Meopham East Junction. One day.................

Incidentally,  the Southern Railway would never use these locos on passenger workings, remembering Sevenoaks.

It was said that as they were being withdrawn from service by B.R., requests for enthusiasts specials were also refused. 

[Oldddudders]

Looks like a W to me, Judge.