Sandringham New Build(s)

Interesting.
I seem to remember pictures of a P2 crank and that was definately buiilt up and constructed mid thirties I think.

 

Unfortunately I do not know the answer to this either but I have asked our Engineering Director the question and will update you when I get a reply. There may be a time lag in responding to you though as you may have noted from my profile, I actually live in Canada! I am a Director of the B17 Steam Locomotive Trust though and edit their quarterly magazine, The Spirit, among other things!

 

Surely even a built up crank axle uses forged axle pieces... cant imagine in this day and age you will find anyone to forge that as one piece...

 

Our Engineering Director has supplied me with the following answer regarding the crank axle -

The Crank Axle will be manufactured using steel forgings to be machined to size for each individual item as follows:-

Both Sweep Webs, the Inner Crank Pin and both Stub Axles are as per the original LNER design, see illustration below. I am unaware of a fabrication which I am sure would disintegrate under the stresses set up. That is why steel forgings are produced in accordance with British Standards which define requirements for chemical content, grain size, strength of material and hardness and the heat treatment and quenching processes. After final machining to definitive sizes, the inner crank pin and each stub axle is fitted in turn to the Sweep Web by heating and shrinking being pressed together and secured with screw key locking fasteners.

 

South Devon Railway Engineering have made several built up crank axles from individual stub axle and crank web components for other new build standard gauge locos and make a lovely job of what they do.

Mike

 

That looks to me to be a built up (fabricated) crank axle rather than a solid forged one. Whether, in this day and age, you would want to forge the individual components is debateable. I would have thought that the quality of a modern wrought steel, such as En24T (817M40T), would be a far better bet than a forged bar with the ever present possibility of forging laps.

 

Big marine crankshafts can be made in fewer parts.
A forged and finish machined throw and two main journals stubs shrunk in place.
Three finish machined parts and two schrinks for a single throw locomotive crankshaft.
.
https://www.researchgate.net/public...ers_influencing_the_thermal_distribution#read

https://dhhiindia.com/product/marine-crank-shaft/

 

Surprises me that the sweep webs would also need to be forgings, but then how else for such chunky bits of metal.

 

It would be fun to hear arguments pro et contra.
Fowler had made a paper ( Solid cranks are not dead dogs ) or something like that
Germany made more than 2000 of these for high rpm and piston thrust
and LNER used 5 pieces of steel to make same job

 

Thanks for that picture Hermod, it does seem to show that the three "throws" of the crank are not quite straight forward, as the two outer crank pins look as though they are "quartered" at 90 degrees to each other - I did wonder if they were all three at 120 degrees to each other but that doesn't appear to be the case??

 

Looking at the photo I'd suggest that the inner crank is slightly after 12 o'clock , the left one (as viewed) slightly after 4 o'clock and the right one slightly after 8 o'clock so the three throws are at about 120 degrees, certainly not 90 degrees in the case of the outside cranks. The true disposition will be dependent on the inclination of the cylinders and whether the inside one is different to the outside.

 

I believe that crank axle is from a Class 44 2-10-0. With more than 2000 built, this was the world's most numerous class of 3-cylinder locomotive.

Multi-cylinder heavy freight locos were never very prolific in Britain. The most numerous were LNWR Webb compound 0-8-0s - 112 of the 3-cylinder Class A and 170 of the 4-cylinder Class B.

The German Class 44s had divided drive with unequal length connecting rods - inside cylinder onto 2nd coupled axle and outside cylinders onto 3rd axle. Imagine if Peppercorn had built a big 3 cylinder 2-10-0 with the boiler and cylinders of his A1 and A2 Pacifics.

 

but

Are you saying that this wheelset (with three cranks) is from a non-German Class 44?

 

It’s got a crank for a centre engine connecting rod and crank pins for the outside coupling rods.

Tom

 

Is this a family figth or can anybody join?

http://dlok.dgeg.de/img_files/br/br44-200.jpg

 

I thought at first that @bluetrain was contradicting himself by saying that the wheelset is from a class of loco that had divided drive. But rather than say that I speculated as to how both statements (this wheelset with three cranks from a Class 44 and German Class 44 having divided drive) might be true if there was some other kind of Class 44. Clarification would be welcome.

No fight happening: just seeking clarification.

 

No - A German Class 44 3-cylinder 2-10-0 with its divided drive arrangement. The inside cylinder is higher and inclined, driving the second coupled axle, while the outside cylinders are lower and horizontal, driving the third coupled axle.

https://en.wikipedia.org/wiki/DRG_Class_44
http://dlok.dgeg.de/img_files/br/br44-100.jpg

Correct.

 

Don't forget that the 3rd coupled axle is also a cranked one (taking the place of an eccentric) to drive the inside Walschaerts/Heusinger valve gear on a 44.

 

If that is the reason for the centre crank in the picture, why does it have such a large throw, apparently the same as that of the outside cranks? I am more inclined to believe that the wheelset in the picture is from a 3-cylinder loco which had all three cylinders driving onto the same axle, like a Sandringham.

 

I think this will answer your question. The inside cylinder drives a crank axle on No. 2 position, while the mini-crankaxle can be seen on the 3rd coupled axle but off-set to the left. This drives the expansion link of the inner valve gear.

Early 44s, up to about 44 065 had a plain axle here with an eccentric. The I believe still surviving BR 85 2-10-2 tank loco 85 007 also had the early arrangement with an eccentric. Anyone know where this loco is? It was at Freiberg by the Black Forest line back in the 1980s.