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DONCASTER LOCOMOTIVE DRAWING OFFICE
Arthur Henry Peppercorn was Assistant Chief Mechanical Engineer (1941-46), CME of the LNER (1946-47) and CME of the E & NER (1948-49).
The frames for both Classes A2 and A1 were modelled on those of Thompson’s Class A2/3, with the front end altered.
Like Thompson, the centre cylinder drove the leading coupled axle, and the outside cylinders drove the intermediate coupled wheels. However, the three cylinders were in line making it possible to locate the bogie in its traditional position.
DIAGRAM 118. The new Pacifics had the Diagram 118 boiler, which was a lighter version of the Diagram 117 fitted to Class A2/3. Although it was basically a Thompson boiler, the finishing touch had been the addition of the perforated steam collector (November 1946). The boiler was fitted to Class A2 Nos. 60525-39 and Class A1 Nos. 60114-62, and was interchangeable with Class A2/3.
All future construction of former LNER types were extensions to Thompson’s building program and no significant changes were needed to their boiler designs.
Both Diagrams 117 and 118 boilers were used for Class A2/2 from 1951, which is hardly surprising as Diagram 117 had been based on Diagram 106A. From 1954 Diagram 107 (the A4 boilers, which were still being constructed down to 1961) were interchangeable with Class A3.
Peppercorn decided (7/1947) on a return to helical bearing springs for new bogies only, a return to Gresley practice. Quoting BR numbers, these bogies were fitted to Class A1 Nos. 60114-62; Classes A2, A2/3 Nos. 60524-39; Class B1 Nos. 61340-61409; Class L1 Nos. 67702-67800. Existing bogies were not brought into line, though after Nationalisation this type of bogie was fitted to five D49s Nos. 62738/41-44 (1949-52). Some B1 bogies had their laminated springs strengthened by the addition of an extra plate, the first engine altered being No. 61236 (December 1952). Though individual bogies were not altered, they may have been transferred to other engines during Works visits.
In “Thompson & Peppercorn - Locomotive Engineers” (Col. H.C.B. Rogers, 1979) the author refers to the unexplained rough riding of the Peppercorn A1s. The “problem” eventually went away with no explanations given, though it may just have been the “newness” of their springs. I also experienced this once, on the 2-0 pm. Darlington – Leeds, a favourite running-in turn for engines fresh off Works. On this occasion (4th June 1949) No. 60148 was the engine and I was almost thrown out of the fireman’s seat with a vicious lurch rounding a curve. The engine was back in Works next day, or so I was informed though the visit was not recorded on its history card.
The thickness of all Gresley bogie frames was increased from 11/8in. to 1¼in. from September 1955 after the derailment of Class W1 No. 60700, caused by the failure of its bogie. The cause of the failure is not known thought the accident report noted it had failed at the site of a weld. No. 60700 was given a new bogie (December 1955), with its frames constructed of 1¼in thick steel plate. After its withdrawal (June 1959) its 3-year old bogie frames were found to be badly cracked which suggested its withdrawal had come none too soon. Part of the problem may have been that because of its unique nature (longer wheelbase) there was no spare bogie for rotation purposes, and it had been continually welded and patched at each repair visit. Prior to its mishap (1st September 1955) it had already had three Doncaster Works visits that year, at the first of which (February 1955) its cylinders were lined up to 19in diam. because of trouble with hot axle boxes and middle big end bearings, so it was already showing signs of old age.
Class A2/2 No. 60506 visited Doncaster Works for repairs eight times in 1952-55. In January 1956 its bogie received auxiliary helical springs to supplement the laminated bearing springs, perhaps in the hope of perfecting a cure. It is not recorded what effect the modification had, but it afterwards visited Works on a further fourteen occasions between then and October 1959 (when Works repairs to this class ceased). In that month Nos. 60502/04/05/06 were all in Works, while the two other A2/2s had both been in Works earlier in the year. Within a couple of months Nos. 60503/05 had been scrapped. No. 60501 was condemned in 1960, and Nos. 60502/04/06 went in 1961. It seems remarkable how they managed to keep running without requiring a visit to Works.
Some B1 bogies also received auxiliary helical springs, but no specific numbers have been noted
There were several incidents post-war involving V2s and put down to their swing-link pony trucks. It was decided in November 1946 to fit the V2s with similar pony trucks to that in Class L1 No. 9000, i.e. with helical spring side control and laminated bearing springs. No. 884 was fitted first (December 1946), followed by six more Nos. 845/63/86, 917/36/43 (April to October 1947). Meanwhile (in July 1947) it was admitted there had been some trouble with the laminated bearing springs on one of these engines and it was decided that future conversions would have helical bearing springs. This new arrangement was fitted to No. 60818 (July 1948) and future conversions were fitted similarly, with the process completed in April 1952.
Classes L1 (production) and K1 (production) appeared after Nationalisation, and they differed from their prototypes in having helical bearing springs.
It was realised in January 1957 that the seven original V2 conversions still had laminated bearing springs, and these were brought into line in 1957-58.
Peppercorn perpetuated Thompson’s improvements, in particular the application of steam brakes.
GROUP STANDARD 4200 GALLONS
No further 4200 gallon tenders were ordered from Doncaster. Instead large numbers were built at Darlington Works, Gorton Works and by contractors, for Classes B1 and K1, many after Nationalisation.
GROUP STANDARD 5000 GALLONS
Many Thompson’s orders were still to be completed, in particular the following.
TO87 (12/6/1944) T.714-18 currently being attached to Thompson’s A2/3 Nos. 519-23.
TO88 (4/4/1945) T.719-28 for Class A2 Nos. 215-24. Eventually attached to Peppercorn A2 Nos. (60)527-36.
(4/4/1945) T.729-33 for Class A2 Nos.
Eventually attached to Peppercorn A2 Nos. 60537/38, A1 No. 60114, A2 No. 60539, A1 No. 60115.
(15/11/1945) T.734-43 for Class A1s.
Would eventually be attached after Nationalisation to Peppercorn Nos. 60116-25.
(15/11/1945) T.744-49 for Class
Would eventually be attached after Nationalisation to Peppercorn A1 Nos. 60128/26/27/29 and Thompson A2/1 No. 60508 (6/1949), 60510 (9/1949).
(15/12/1945) T.700-03 for Class
A2/1 Nos. 3696-99.
Only three new tenders were built to this order and attached to Thompson A2/3 Nos. 524 and Peppercorn A2 Nos. 525/26 (the last one after Nationalisation).
On the eve of Nationalisation Peppercorn placed fresh orders at Doncaster as follows:
TO93 (about 11/1947) 10 Class A2. This was cancelled after Nationalisation (4/5/1948).
TO94 (about 11/1947) 3 Class A2. This was cancelled after Nationalisation (4/5/1948).
TO95 (about 11/1947) 7 Class A2. This was cancelled after Nationalisation (4/5/1948)
TO96 (about 8/1948) T.773-82 for Class A1 Nos. 60153-62.
A further 23 A1s were built after Nationalisation at Darlington Works, Nos. 60130-52, attached to T.750-72.
Doncaster subsequently built LMS type tenders and BR Standard tenders.
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