Sir Nigel Gresley - The L.N.E.R.’s First C.M.E.

Under the Route Availability classification developed by the LNER in the 1940s, the V4 was in RA4 (max axle-load 17.5 tons) while the B1 was in RA5 (max axle-load 18.125 tons).

From RCTS survey of RA situation in 1947, it is clear that relatively few lines were in RA4 at that date. The most significant routes were the GNSR coast route to Elgin via Buckie and the Ballater, Fraserburgh and Peterhead branches, all of which were RA4 with B1 additionally allowed. (The GNSR main line from Aberdeen to Elgin via Craigellachie had been upgraded to RA6.)
Other RA4 routes were the Lossiemouth branch, Lochty branch (goods-only) in Fife, some Bathgate area colliery branches, Essendine to Sleaford & Essendine to Stamford (with K2 and some other GN RA5 types additionally permitted), Dereham & Swaffham area branches (with Clauds, J19 & N7 additionally permitted) and Tivetshall to Bungay.

That leaves me puzzled as to why the V4 was designed down to a 17 ton axle-load, when 18 ton would have barely affected its route availability. Possibly more routes had the lower axle-load limit when the V4 was being designed in 1939, but were subsequently upgraded for heavy wartime traffic.

EDIT: Missed a couple of RA4 routes -Whitby to Loftus and M&GN Sutton Bridge to South Lynn (with some RA5 locos also permitted).

 

If I may - RA4 would have given it 80% percentage coverage when built over the LNER system. I question if this was entirely necessary. The B1 by comparison was, I think, with a back of the cig packet maths, came out around 75%. The difference of 5% seems a lot but it's mostly secondary routes.

The issues of locomotive availability weren't just on more lightly laid lines but were physically across the whole of the LNER. The age of the locomotives in the pre-grouping group in particular was an issue, together with spares/availability and the sheer number of boiler types being manufactured.

 

Eee .... that LNER had it easy, lad. If you want to see real problems with spares inventory, a crazy number of boilers and truly dire budgetary circumstances, I suggest you get your paws on Clements & McMahon's 'Locomotives of tGSR' Publisher: Colourpoint Books ISBN: 9781906578268

 

The RA/weight of a given type especially of new locomotives has since almost time immemorial caused issues between on the one hand the CME/Superintendent and CCE [Chief Civil Engineer]. Keeping it North of the Border the classic case being the Highland Railway Castle class as it was found they fell foul of the RA/weight issues and were sold on brand new/second hand to the Caledonian, they were built IIRC about 40 years earlier than the V4s. The Castles eventually I believe running on the Highland after Grouping when the line it's RA upgraded....

 

You mean the River class.

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Come to think of it yes.......wasn't sure off hand.

 

Even if there aren't many RA4 routes something still has to run the services, so if they could get the desired capability into a lighter package then why not.
But I imagine you're right that routes were upgraded during the war. On the western at least bridge replacements were made to a higher standard than the current weight limit, so lines were gradually upgraded as a matter of course, and there were some significant GWR routes upgraded for wartime traffic, notably Didcot Newbury and Southampton and some Cambrian lines.

 

It would be interesting to know if Gresley had any specific routes in mind where he wanted the V4 to operate. The V4 weight seems to have fitted the GNS section better than anywhere else.

A more general comment on locomotive policy is that the LNER built a large number of locos in the highest RA8/9 axle-load categories - the Pacifics, V2, K3 & D49. Whereas the GWR only had the 30 Kings up at this level. By 1947, the LNER had upgraded the GE main lines to RA7 but the BR Britannias were the first engines able to take advantage.

 

that was after the J50 (1913)
i can't find the ref , but it was when Holcroft gave an address to the Inst of Mech Eng. i think C1917. ---others will know !


what happens when you put 6ft drivers on a B17? (RA5) . ---something a lot cheaper than a V4 i wager

 

More to the point while its hardly cutting edge why didnt they build more B12's in the 1920's?

 

they built the B17 instead .

 

They built ten in 1928.

 

They did indeed build more B12s - albeit Lentz gear fitted ones.

 

The B17 was 77 tons and V4 was 70 .Ergo 10% cheaper
If having 6feet wheels mass is approximately 3 tons less. so V4 is only 5% cheaper

 

talking cost not weight .

V4 new tooling . expensive alloys . very expensive firebox , design costs etc.

B17 . other than wheels and a bit of work on the frames , most of it is off the shelf . drop the BP or it will be in Cl 7 -- save on boiler maintenance.
B17 probably 25% cheaper + economies of scale and better valve gear

 

I need to go and check the exact figures but the B1 was significantly cheaper to build than a V4. Off the top of my head might have been a 1/3 cheaper. I’ll check when I can and report back.

 

B1 had ca 10% bigger firebox(copper) and it was more tricky to make and install.
The real drawback with uncompensated british 2-6-2s is more likely the unreliable adhession.

 

On the Gresley 3 cylinder valve gear, one of the other applications of it were on some 4-12-2s that the Union Pacific in the USA built. They found it to be a maintenance problem and it was removed from some of the class.

 

However, later builds had roller bearings fitted to the conjugated motion and the class was considered a success.
https://www.steamlocomotive.com/locobase.php?country=USA&wheel=4-12-2&railroad=up#290

 

Ditto NZGR's way too powerful Class G Garrats of 1928, which as early as 1937 were dismantled, with components used to create a class of 'pacifics'.

The conjugated valve gear on these locos, modelled on Gresley's principals, was problematic from the start and it's retention on the resultant pacifics (also designated G Class) was a factor in their being the first mainline class to succumb to diesels, in 1955/6.

This was another example of a railway's own CME (in this case, Mr. G.S. Lynde) believing he could design a loco better than Beyer Peacock. The evidence everywhere suggests customers were usually far better off trusting Gorton's D.O