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

Belatedly, from above:

I would suggest that the Chief of the Motive Power Department of the Sud-Est would have known more about the reliability of the 240Ps than Mr Durrant!

https://www.martynbane.co.uk/france/lemistral07/241p.html

 

An updated list of locomotives built, rebuilt or influenced by Chapelon.

Built/Rebuilt/Modified:

231 Est 051 to 073 23
231 PO 3701 to 3731 31
231 Nord 3.1111 to 3.1130 and 3.1171 to 3.1198 48 (Second batch new)
231 PO 3801 to 3806 and 3821 to 3829 15
140 PO 5001 to 5067 67
231 PO 3601 to 3650 50
141P SNCF 318 (New)
240A/240P 37
160A1 1
242A1 1
142 GELSA 66
242 GELSA 24
141R 165

Influenced:

150 Nord 5.1201 to 5.1230 30
150P 115
État 231-501 to 231-783 215
231 PLM 2 to 86 84
231G entre 2 to 285 284
140J 170
141 D 124
141 E 254
141 F 195
141R 640
Est 230K 177
Est 231B 40
231 H 30
241 Est 241002 to 241041 and 241 État 241-001 to 241-049 90
232R 3
232S 4
232U 1
241P 35
Czech Series 556 510
RENFE 141 F 240
PLM 5-231 E 71
PLM 5-231 H 30
PLM 5-241 D 145
PLM 5-241 E 27 1
PLM 5-150 A 10
PO 231 4500 to 4570 33 (remainder converted to 240P)
PO 231 4571 to 4600 30
Est 1-230 3501 t0 3890 36
Etat 3-141 C 250
Etat 3-231 D 135
Etat 3-231 DD 31
Etat 3-231 W 21
Etat 3-231 H 92
Etat 3-231 R 6
Etat 3-231 C 24
AL S14 1-231 B 60
LNER A2 6
LNER Peppercorn A1 49
LNER A1/1 1
LNER A2/1 4
LNER A2/2 6
LNER A2/3 15
LNER/BR A3 79

LNER A4 35
LNER P2 6 (Kylchap not fitted to 2005 but fitted to 2007)
LNER/BR V2 8
BR 71000 1
BR 60163 1
CSD 387.001 6
CSD 475.1 172
CSD 476.001 3
CSD 498.0 40
CSD 498.1 15

Total 5,558

All of the second series of 141R were equipped from new with Kylchap exhausts. A large proportion of the first series of 141Rs were also subsequently equipped with Kylchaps but as numbers are not available, they have not been included.

 

I think "Dusty" Durrant opinions need to be taken with a pinch of salt. Remembering that he was Swindon trained AND noting that Swindon opinions replaced the designated Kylchap chimney on 71000 with a standard Swindon double chimney hence part of the reasons for its poor steaming in BR days suggests that Swindon standards may not be the best guide to locomotive performance. Having met Dusty during visits to South Africa I can vouch for his self opinionated personna but he was an engagingly memorable character especially when discussing his love of Beyer Garrets.

 

Gresley’s largest fault full-stop was his conjugated valve gear. No doubt about it. I’m not even going to discuss the multiple mechanical faults which are well known, but I’m going to tackle the part of it less discussed, the fact that the arrangement of it forced the steam chests to be much smaller than they should have been.

Gresley settled on 10” piston valves in the pre-war years, which was a pretty decent size for the time, following on from Churchward’s figures. However, the arrangement of the three cylinders forced him to reduce the diameter down to 8” which was grossly inadequate for locomotives the size of the pacifics, with three 19” or 20” cylinders, and this coupled with the short-travel valve gear (another byproduct of the cylinder arrangement) is why the A1 was an embarrassment running next to the Castle. It’s pretty interesting as well that it literally took years of harassing Gresley for him to finally and reluctantly increase the valve travel.

I would wager the Pacifics (and all of Gresley’s big engines) would have been vastly better performers if they were given three independent sets of gear and more appropriate sized steam chests. Gresley is a good example of the fact that it doesn’t matter how great your boiler is, if the power can’t be transmitted effectively, it can completely ruin a design.

I don’t even need to mention how the B17 was an embarrassment for Doncaster. No matter how many options the draughtsmen tried, they couldn’t get Gresley’s three cylinders to fit within the length and weight restrictions. The situation got so bad they were forced to go to NBL, and even the latter couldn’t make it completely work. Or how the D49 was a pretty lackluster design next to its most comparative contemporary, the Southern ‘V’ class.

 

YAWN.

 

“I’m going to show that I don’t care by taking the effort to respond in the first place.”

 

In 1924 we are talking £10000 Sterling to purchase rights for valve gear. Indeed, the Silver Links sustained pulling over 100mph proved it more than a match for anything else on the rails.
Ingenerio Caprotti's might have an edge, but the rights and the fact the whole thing quickly wore out made it the F1 design. And the Walschaetts would have meant and entire retooling of workshops, I'd imagine.

 

I'm not disputing your suggestion per se. However it's interesting that you suggest the Pacifics would have been much better performers is they had independent valve gear and appropriately sized steam chests (i.e. if they had the same arrangement as Thompson and Peppercorn Pacifics) when it's difficult to argue that in their final forms they were still very competent locomotives. Yes fitting Kylchap exhausts improved them but given that members of almost every Class 7/8 express design in use in the 50s ran with double chimneys or multiple blast pipes I don't think you can hold that against them, it was more a development every top link loco was given. Few locos can match an A4 for speed, the A3s were solid and reliable, and the V2s (which we can probably lump in the same category as they were effectively an A3 with one of the leading wheels removed) are often considered some of the finest large mixed traffic engines ever built in Britain. Then during the war they took excessively heavy loads (more than one recorded instance of 26 coaches out of Kings Cross with the loco starting in Gasworks Tunnel!). I wonder if in the case of the Pacifics the large boiler and/or larger locomotive size helped hide the drawbacks of the smaller steam chest?
And, were Mallard built with what you would consider appropriately sized piston valves and steam chest, how much faster than 126mph do we think she may have been able to run in July 1938?

 

…. and yet even today his A4s continue to put in remarkable performances on the mainline and the crews don’t have to crawl around inside the frames to prep the loco, unlike those of some other designers locos I could mention.

 

Have you ever oiled up an A4? You still have to crawl around inside to get at the big & little ends. Nothing like as bad as some, though.

 

"Osmium"....well known for it's extreme density....