A2  60500 – 60539  4-6-2  LNER  Thompson & Peppercorn  

a2.jpg

Power Classification 7MT and 6MT
Introduced 1943 – 1948
Designer Peppercorn and Thompson (2 Gresley rebuilt by Thompson)
Company LNER
Weight – Loco 101t 0cwt, 101t 10cwt and 98t 0cwt
               Tender 60t 7cwt
Driving Wheels 6ft 2ins
Boiler Pressure 225psi and 250psi superheated
Cylinders Three – 19in x 26in and three – 20in x 26in
Tractive Effort 36,385lbf, 40,320lbf and 40,430lbf
Valve Gear Walschaert (piston valve)

The A2 class actually consisted of four distinct sub-classes of mixed traffic locomotives built by Thompson and Peppercorn.

Thompson’s pacifics were designed on quite different plan from Sir Nigel Gresley’s. They all had three sets of cylinders with divided drive, the inside cylinder driving on the leading coupled axle and the outside cylinder driving on the second axle. Three independent sets of Walschaert valve gear replaced Gresley’s conjugate gear. They had coupled wheelbase about one foot longer than Gresley’s pacifics and were all fitted with double chimneys (at first unlipped chimneys, but later chimneys with lips were fitted).

Number in Service.

A2

A2/1 A2/2 A2/3

Total

1943 1

        1

1944

3

6

        9

1945 4 6

      10

1946 4 6         9

      19

1947

        1

4 6       15

      26

1948-58

      15

4 6       15

      40

1959

      15

4 4       15

      38

1960

      15

1 3       15

      34

1961

      15

      15

      30

1962

        7

        7

      14

1963

        5

        3

        8

1964

        5

        3

        8

1965

        3

        3

A2/2  60501-60506

a2-2

Power Classification 7MT
Introduced 1934 – 1936 rebuilt as A2/2  1943 – 1944
Designer Thompson
Company LNER
Weight – Loco 101t 10cwt
               Tender 60t 7cwt
Driving Wheels 6ft 2ins
Boiler Pressure 225psi superheated
Cylinders Three – 20in x 26in
Tractive Effort 40,320lbf
Valve Gear Walschaert (piston valve)

On succeeding Gresley, Thompson started a process of standardisation. His first proposal concerned a mixed traffic Pacific. This was basically a mixed traffic non-streamlined A4 with Walschaerts valve gear on the centre cylinder. This design would replace the P1, P2, and V2 classes, along with some of the work being performed by the B7, B16, and K3 classes. Thompson started by rebuilding the P2s.

The P2s locomotives were three-cylinder P2 class 2-8-2 engines, built in 1934-1936 for the line between Edinburgh and Aberdeen, but the wheelbase was found to be too long for the continuous curves of this line. Also, the swing-link pony truck was causing damage by adding unnecessary stress to the frames. A similar pony truck arrangement on the V2s would eventually by fixed, but Thompson decided to approach the problem on the P2s with a complete rebuild.

 p2 P2 class as introduced by Gresley in 1934
 v2 V2 as introduced by Gresley in 1936
 a2-2 A2/2 as introduced by Thompson in 1943

As rebuilt they retained their original boilers (although they were shortened by 2ft) and they were classified A2/2. Existing parts were used as much as possible, including the short outside connecting rods. This led to the outside cylinders being mounted relatively far back. The Gresley conjugated gear on the middle cylinder required a high level of maintenance, so Thompson replaced this with Walschaerts valve gear. For clearance, this meant the middle cylinder had to drive the leading driving axle. A Kylchap exhaust arrangement was fitted, as well as small wing-type smoke lifters. The first engine diagram appeared in August 1942 and rebuilding occurred between 1943 and 1944 at Doncaster.

Under the 1943 renumbering scheme, they would have been numbered 990-5, but they did not receive their new numbers until after the 1946 renumbering scheme when they received the numbers 501-6. They then received the British Railways numbers 60501-6 but retained the names that they had been given as P2 class locomotives.

The A2/2s are often considered the least successful of Thompson’s Pacific designs, but it has to be borne in mind that he was working with the flawed P2 design. They differed from the other A2 locomotives in not carrying smoke deflectors.

Number in Service.

Built Withdrawals No. in Service
BR Numbers Quantity
1943 60505

1

1

1944 60501-4 & 60506

5

     6

1945-58

6

1959 60503 & 60505 2

4

1960 60501 1

3

1961 60502, 60504 & 60506 3

0

Locomotive allocations during British Railways operation

Depots as of January

1948

1950 1955 1960

1961

Aberdeen Ferryhill

2

Haymarket

4

1

New England

2

3 2

2

York

3

3 2

1

6

6 6 4

3

Locomotive allocations during British Railways operation

After rebuilding, the six A2/2 locomotives returned to Scotland to work the Edinburgh to Aberdeen line. They were disliked by their Scottish crews as they tended to slip badly.

At the end of 1949, they moved to England and were divided between the York and New England sheds. They kept their tablet exchange apparatus during the rebuilds, but this was removed after they were transferred to England.

 

A2/1  60507-60510

a2-1

Power Classification 6MT
Introduced 1944 – 1945
Designer Thompson
Company LNER
Weight – Loco 98t 0cwt
               Tender 60t 7cwt
Driving Wheels 6ft 2ins
Boiler Pressure 225psi superheated
Cylinders Three – 19in x 26in
Tractive Effort 36,385lbf
Valve Gear Walschaert (piston valve)

The next four Thompson pacifics appeared in 1944 and they were classified A2/1. They were originally ordered as V2 class 2-6-2s but they were redesigned as pacifics with B1 bogies, 19in diameter cylinders and steam reversers. The V2 boiler was retained, although the pressure was increased to 225psi. These were built at Darlington, unlike the V2s which were all built at Doncaster.

Compared to the V2s, the A2/1s had a number of innovations. The firebox had a rocking grate and hopper ashpan, which greatly simplified the process of dropping the fire and emptying the ash from the grate. Thompson also introduced an axle-driven alternator and electric lighting on the A2/1, which he later used on some of his other locomotive designs.

 v2 V2 as introduced by Gresley in 1936
 a2-1 A2/1 introduced by Thompson in 1944

To standardise the new inside motion with that of the A2/2s, the coupled wheelbase was reduced.

They were originally fitted with 4,200 gallon six-wheel tenders but, these were all replaced with eight-wheel tenders by 1950. In 1945, 3696 (60507) was given the 8-wheeled tender from A4 4469 Sir Ralph Wedgwood which had suffered irreparable bomb damage. The remaining three A2/1s received 8-wheeled tenders in 1949.

The A2/1s were originally fitted with wing-type smoke deflectors. After the A2/3s appeared in 1946 with their large smoke deflectors, it was decided to replace these deflectors with the large kind.

Number in Service.

Built Withdrawals No. in Service
BR Numbers

Quantity

1944 60507-9

3

3

1945 60510

1

4

1946-59

4

1960 60507, 60509 & 60510 3

1

1961 60508 1

0

Locomotive allocations during British Railways operation

Depot as of January

1948 1950 1955 1960

1961

Haymarket

2

3 3

3

Kings Cross

2

1

New England 1 1

1

4

4 4 4

1

A2/3  60500, 60511-60524

A2-3

Power Classification 7P
Introduced 1946 – 1947
Designer Thompson
Company LNER
Weight – Loco 101t 10cwt
               Tender 60t 7cwt
Driving Wheels 6ft 2ins
Boiler Pressure 250psi superheated
Cylinders Three – 19in x 26in
Tractive Effort 40,430lbf
Valve Gear Walschaert (piston valve)

In 1944, Thompson authorised the building of thirty standard pacifics based on his A2/2 design (his rebuild of the P2s). The boiler pressure was increased to 250psi, and the cylinder diameter was reduced to 19in. A further thirteen were authorised in 1945, although these and half of the original order were actually built as Peppercorn A2s. A total of fifteen were built to Thompson’s design between 1946 and 1947.

These were the first new pacifics built at Doncaster for eight years. Hence, they were marked by a number of innovations, including steam brakes, a hopper ashpan, electric lighting, and a self-cleaning smokebox. However, the rocker gate and V-shaped cab (as seen on some of Thompson’s rebuilds) were absent.

60500 Edward Thompson which was completed in May 1946 was the 200th locomotive to be built at Doncaster.

Initially, the design included the small wing smoke deflectors, but these were changed to the large smoke deflectors before any of the A2/3s were built.

At first, the A2/3s worked short distance trains whilst teething problems were fixed. The main problem concerned the steam pipe which ran from the dome to supply steam to the injectors, ejectors, etc in the cab. Compared to the Gresley pacifics, the boilers were shorter and the steam-operated brakes were much more effective. Hence, braking would cause boiler water to slosh forward and some would be taken into the steam pipe. This could cause the injectors to fly off if they were in use. Also, when the ejectors were next used, they could send the trapped water through the ejector pipe and out the chimney – drenching anyone in the vicinity. This problem was fixed by adding an extension to the steam pipe. This pipe was kept as high as possible, allowing the water to drain back into the boiler. A drain valve was also added to the ejector exhaust pipe. Most of the A2/3s had these modifications fitted from new.

Comparison tests with the V2s were performed. This showed little doubt that the double blastpipe and chimney on the A2/3 was superior to the V2 arrangement, but that the A2/3 smokebox temperature was higher. This latter point resulted in more lost heat through the chimney. The final conclusion was that the A2/3s were wasteful of coal on light runs, and that their greater capacity could only be effectively utilised on heavier duties.

Number in Service.

Built Withdrawals No. in Service
BR Numbers Quantity
1946 60500 & 60511-18

9

      9

1947 60519-24

6

    15

1948-61

    15

1962 60511, 60514-19 & 60521 8

      7

1963 60500, 60513, 60520 & 60523 4

      3

1964

      3

1965 60512, 60522 & 60524 3

      0

 

Locomotive allocations during British Railways operation

Depot as of January

1948 1950 1955 1960 1961 1962 1963 1964

1965

Aberdeen Ferryhill

1

Doncaster

1

2

2

Gateshead

2

2 2

2

Haymarket

1

1 1 1

1

Heaton

5

5 2 2

3

Kings Cross

4

1

New England 4 5 5 3 3

4

Polmadie 3

3

St Margarets 1

2

Tweedmouth

3

York

2

2 5 5 6

6

15

15   15   15     15 15 7 3

3

 

A2  60525-60539

a2 -0 .jpg

Power Classification 7MT
Introduced 1947 – 1948
Designer Peppercorn
Company LNER
Weight – Loco 101t 0cwt
               Tender 60t 7cwt
Driving Wheels 6ft 2ins
Boiler Pressure 250psi superheated
Cylinders Three – 19in x 26in
Tractive Effort 40,430lbf
Valve Gear Walschaert (piston valve)

The A2/3s were Thompsons new design and they had the boiler pressure increased to 250psi. Originally thirty were ordered, but only fifteen were actually built, fifteen were built after Thompson’s retirement. In fact, the Chief Draughtsman had already started to design a modified A2/3 in 1946, without the authorisation of Thompson. The other fifteen thus appeared as Peppercorn A2 class.

The design continued to be amended through 1946 and 1947, with the first Peppercorn A2 completed (525 A.H.Peppercorn) was outshopped from Doncaster in December 1947 on the eve of nationalisation.

This design kept Thompson’s cylinder and valve arrangement, but had a more conventional bogie position and hence a shorter wheelbase. Also, the exhaust ducts from the outside cylinders were amended. A rocking grate was also fitted. The Kylchap exhaust was discarded from the design, but the self-cleaning smokebox was kept. As the A2 smokebox was shorter than the A2/3 smokebox, it would not have been possible to have kept both the Kylchap exhaust and the self-cleaning apparatus.

During these design modifications, the order size increased from the original fifteen to thirty-five. However in May 1948, the last twenty were cancelled pending the results of the BR Interchange Trials.

The last A2 to be built, 60539, was fitted with a Kylchap exhaust when built. Due to the limitations of the smokebox size, the self-cleaning apparatus was discarded. This appears to have been a success, as five more of the class were similarly modified in 1949.

During trials, the A2s tended to be slightly less economical than the Peppercorn A1s, but noticeably more economical for the high power tests. These tests showed problems with the boiler design being used. The same tube arrangement was used irrespective of the boiler length. This was corrected with a large firegrate, which resulted in high coal consumption.

Initially the A2s were based at depots the length of the East Coast Main Line, ranging from New England (Peterborough) in the south to Edinburgh’s Haymarket. In 1949 five were put to work on the Edinburgh-Dundee-Aberdeen route and proved the ideal engines for its stiff gradients and sharp curvature. The A2s also worked to Perth, Glasgow, Carlisle, Newcastle-upon-Tyne and occasionally more southerly outposts. In 1963 Nos.60525, 60530 and 60535 surprisingly crossed the LNER-LMSR divide and were allocated to a Glasgow depot, Polmadie. They replaced ex-LMS Coronation Class over the ex-Caledonian Railway route to Carlisle.

The swansong of the A2 came in eastern Scotland with many memorable performances over the Aberdeen road during the early 1960s. In 1961 on Stoke bank in Lincolnshire, the location of Mallard’s 1938 world speed record, No.60526 Sugar Palm achieved 101 mph (163 km/h). Withdrawal of this fine class of locomotive began in the following year. Neither 60526 nor No.60525 A. H. Peppercorn, named after the third and last Chief Mechanical Engineer of the London and North Eastern Railway, were preserved.

In 1949, five moved to Scotland to make up for deficiencies with the A2/2s (rebuilt P2s). By November, the A2/2s had been replaced with further Peppercorn A2s. These Scottish A2s were mainly used on express passenger services between Aberdeen and Edinburgh, which benefited from their greater power and acceleration.

The English A2s worked a variety of services, including express passenger, slow passenger, and parcel services. 60526 Sugar Palm was allocated to York and was regularly used to replace failed locomotives on the East Coast Main Line. Hence, it could often be found anywhere between Newcastle and London. In 1961, it set a speed record for the class of 101mph whilst descending Stoke Bank.

The A2s allocated to England were withdrawn between 1962 and 1963. The three remaining Scottish locomotives were withdrawn in 1966. One of these Scottish engines, 60532 Blue Peter, was sold into private ownership.

Number in Service.

Built Withdrawals No. in Service
BR Numbers Quantity
1947 60525

1

1

1948 60526-39

14

15

1949-61

15

1962 60526/29/31/34/36-39 8

7

1963 60525 & 60533 2

5

1964

5

1965 60527 & 60535 2

3

1966 60528, 60530 & 60532 3

0

Locomotive allocations during British Railways operation

Depot as of January

1948 1950 1955 1960 1961 1962 1963 1964 1965

1966

Aberdeen Ferryhill 3 3 3 5 3

2

Copley Hill

3

Doncaster

1

1

1

Dundee Tay Bridge 2 2 2 2 2 2 3

3

Gateshead

4

1

1

Grantham

2

Haymarket

1

5 6 6

6

Heaton

1

1 1 1

2

New England

1

2 1

1

Polmadie 3

2

St Margarets 6

2

Tweedmouth

2

York

4

1 1 1 1

1

 15

 15  15  15  15  15 7 5 5

3

Initially the A2s were based at depots the length of the East Coast Main Line, ranging from New England (Peterborough) in the south to Edinburgh’s Haymarket In 1949, five moved to Scotland to make up for deficiencies with the A2/2s (rebuilt P2s)

and were put to work on the Edinburgh-Dundee-Aberdeen route and proved the ideal engines for its stiff gradients and sharp curvature. The A2s also worked to Perth, Glasgow, Carlisle, Newcastle-upon-Tyne and occasionally more southerly outposts. In 1963 60525, 60530 and 60535 surprisingly crossed the LNER-LMSR divide and were allocated to a Glasgow depot, Polmadie. They replaced ex-LMS Coronation Class over the ex-Caledonian Railway route to Carlisle.

The English A2s worked a variety of services, including express passenger, slow passenger, and parcel services. 60526 Sugar Palm was allocated to York and was regularly used to replace failed locomotives on the East Coast Main Line. Hence, it could often be found anywhere between Newcastle and London. In 1961, it set a speed record for the class of 101mph whilst descending Stoke Bank.

Accidents and Incidents

  • On the 7th January 1957 locomotive 60520 Owen Tudor was hauling the eleven coach 7:10pm express from Aberdeen to Kings Cross when it ran into the rear of a local train near Welwyn Garden City station. The local six coach train of the 6:18am Baldock to Kings Cross had been cleared to depart from the station and run ahead of the express on the main line to Hatfield. The signalman had set the distance signal at caution and the outer and inner home signals at danger but the express train passed the caution signal without slowing and then passed the danger signals. It then ran over the emergency detonators outside the signal box before running into the rear of the local train at 60-65mph.
    • Two coaches at the rear of the local train were overturned and the last one was wrecked. The engine hauling the express also overturned and the leading six coaches derailed but remarkably there was little damage to the all steel bodies of these coaches. One person in the rear coach of the local train was killed and 25 of the 44 injured were taken to hospital including with the driver of the express train.
    • The accident happened the in misty weather and was soley due to the driver passing danger signals.

 

  • On 1st October 1994 during the first run of a preserved steam locomotive from Edinburgh to Newcastle, 60532 suffered extensive damage during a catastrophic uncontrolled wheel slip.
    • During an unscheduled stop at Durham station the inexperienced footplate crew overfilled the boiler. As the train departed south across Durham viaduct an initial slip was poorly controlled by the driver, who then reopened the regulator too early, probably worried about stalling on the bank up to Relly Mill. The force of the initial slip caused the boiler to prime, carrying water over into the regulator valve and jamming it open. This allowed passage of steam through to the cylinders, perpetuating the slip and accelerating the driving wheels. When the driver attempted to wind the reversing gear back into mid-position to halt the slip, the force of the motion spun it into full-forward position, and the driving wheels reached a rotational speed of 140 miles per hour before the cylinder heads blew off and the motion disintegrated.
    • The driver suffered major injury to his arms, as a result of the screw reversing lever whipping around when he released it. The accident brought to light the importance of train crews being trained on the specific locomotives they were driving, rather than simply a common general instruction on steam locomotives. Neither the driver or fireman had ever worked 60532 before, and were unaware of the locomotive’s sensitivity to priming, which led to the accident.
60512 Perth July 1965.jpg 60512 Steady aim at Perth-July 1965. after being based at Heaton and then York the locomotive moved north to St Margarets (eddinburgh) in 1962. It was withdrawn from service at Dundee in June 1965 and scrapped in October 1967.
60530 Dundee July 1965.jpg 60530 Sayajirao on Dundee Tay Bridge shed-July 1965. It was based at New England (Peterborough) for the first two years of its working life but was the always based in Scotland. It was withdrawn from service at Dundee in November 1966 and scrapped in March 1967.
60528 Carlisle December 1965.jpg 60528 Tudor Minstrel at Carlisle-December 1965. 60528 also spent almost its entire life based in Scotland. The exception being a little over a year based at Gateshead. It was withdrawn from service at Aberdeen Ferryhill in June 1966 and scrapped in October 1966.
60528 Carlisle April 1966.jpg 60528 Tudor Minstrel at Carlisle-April 1966.

Preservation

Back to LNER

Back to Locomotives