B1  61000 – 61409  4-6-0  LNER  Thompson  Antelope  



Power Classification 5MT
Introduced 1942 – 1952
Designer Thompson
Company LNER
Weight – Loco 71t 3cwt
               Tender 52t 0cwt
Driving Wheels 6ft 2ins
Boiler Pressure 225psi superheated
Cylinders Outside – 20in x 26in
Tractive Effort 26,880lbf
Valve Gear Walschaert (piston valve)

The B1 class was Thompson’s first new design for the LNER. Gresley, who preceded Thompson, had had a policy of only creating new locomotive types when necessary whereas Thompson had a plan to standardise designs and thus replace the various engines which had been inherited from many of the companies which had been absorbed into the LNER. The result of the Gresley approach was to minimise the cost of constructing new locomotives but resulted in few parts being common to a variety of engines.

High on Thompson’s standardisation plan, was a mixed traffic 4-6-0 type. Initially designated as class B, they had been reclassified to class B1 by the time the first locomotive 8301 Springbok had been completed in 1942. The pre-existing Class B1 were reclassified as Class B18. The B1 design was intended to replace all of the 4-6-0s (excluding those replaced by the pacifics), all of the heavy 4-4-0s, the D11 4-4-0s, the D49 4-4-0s, the passenger atlantics, the K2 2-6-0s, the K3 2-6-0s, the J6 0-6-0s, the J39 0-6-0s, and other high speed 0-6-0s. Most of these replacements were achieved in practice – a compliment to the standardisation process.

 K2 small K2 introduced by Gresley in 1912
 b17 small B17 Sandringham class introduced by Gresley in 1928
 B1 B1 introduced by Thompson in 1942

The Thompson B1 would quickly become the most successful of Thompson’s locomotive designs and a total of 410 were built by the LNER and British Railways (BR

The B1s were general mixed traffic engines and could be compared with the LMS Stanier Black Five locomotives and the GWR Halls. The B1 designed it had the additional requirement of having to be cheap because, due to wartime and post-war economies, the LNER, never the richest railway company, had to make savings. They were however popular engines and they worked all over the former LNER system.

 Black 5 Stanier black five introduced on the LMS in 1934
 Hall small Hall class introduced on the GWR by Collett in 1924
 B1 B1 introduced by Thompson in 1942

The initial proposal for a 4-6-0 was based on the B17 class but with only two cylinders. The cylinders were to a standard type (based on those used on the K2 2-6-0s), as was the boiler, and the bogie. The first engine diagram was produced in November 1941, and closely resembled the classic Gresley look of the B17 class. The Diagram was simplified in 1942, especially in the areas of the cab, running plate, and steam pipe casings. This was due to Thompson’s desire to keep the design simple for maintenance, construction, and standardisation. This was especially important in the wartime conditions of the time. The boiler pressure was also increased to 225psi. The B17‘s long front overhang was also reduced. This was originally due to the B17‘s third cylinder which had been excluded from the B1 design.

Thompson introduced a new type of bogie design to the LNER with the B1’s bogie. The centre rubbing plates found on preceding Doncaster bogies were removed, and the load was transmitted to the bogie frames through spherical side bearers attached to the engine frame instead. The bogie design went through a number of variations, mainly in regard to the stretcher plates. After the Second World War, the fabricated stretcher plates were replaced with castings. Laminated bearing springs were also replaced with helical springs. Earlier bogies with laminated springs tended to break, and from 1952 an extra plate was fitted to the spring rather than replacing the bogie with a later variant.

The first standard boilers were ordered near the end of 1941, but serious construction of the first batch of ten B1s would not start until the middle of 1942. The first B1, number 8310 Springbok was completed in December 1942 but it was June 1943 before the next locomotive was completed, and the last locomotive of the initial batch would not be finished until the middle of 1944.

A second batch of thirty were ordered in May 1944, but large scale construction did not start until 1945 when the LNER announced a five-year modernisation programme. This programme included a total of 400 B1s in addition to the original batch of ten. Construction of these 400 locomotives was much quicker than the original batch of ten. All were built between 1946 and 1952 in a total of eight batches. A batch of 150 locomotives was built by the North British Locomotive Co between 1947 and 1948. This was the largest single batch of engines which the LNER ever ordered.

The first locomotive 8310 Springbok was named in honour of a recent visit by General Smuts. This continued by officially naming the B1s the Antelope class, although they also acquired the unofficial name of Bongoes after 8306 Bongo. The first forty engines to be turned out from Darlington were named after various species of Antelope which gave the class its name. As the number of engines increased it was impossible to find enough antelope species to continue this naming policy, and, apart from some engines named after directors of the company, most of the remaining locomotives remained un-named.

The only B1 named after Nationalisation of the railways in 1948 was 61379 Mayflower which was named in 1951. Mayflower also carried a plaque stating “This locomotive was named Mayflower 13th July 1951 as a symbol of the ties between the two towns of Boston and of the lasting friendship between the USA and the British Commonwealth”.

In 1943, 8303 Impala was comprehensively tested on various LNER lines in Scotland. The B1s proved to be excellent at starting, which was particularly important on the Scottish lines which had many stations on gradients. Despite the use of poor quality wartime coal, these tests demonstrated the B1’s free steaming capabilities and fast acceleration. This acceleration was important for the running of efficient semi-fast passenger services. One negative aspect of the tests, was that Impala tendency to move unevenly when operating at cut-offs below 25% which was thought to be due to high cylinder compressions. This problem is considered to have caused many drivers to use the regulator rather than the reversing gear.

The post-War B1s had reverse sanders fitted, along with hopper ashpans. The latter removed the need for men to go underneath the locomotive to empty the ash. The original batch of ten B1s (Nos. 1000-9) were fitted with forward-only sanders. They were never fitted with reverse sanders or hopper ashpans.

Self-cleaning smokeboxes were trialed in 1946, and they were also fitted to Nos. 1190-61359 when they were built. Further variations were tried in an attempt to improve the circulation of the hot gases. Continental-style spark arrestors were introduced from 1950, but these tended to clog with soot. Clogging was actually worse than the self-cleaning smokebox grid design, due to the smaller area of the spark arrestor. In 1959 a Western Region spark arrester was tried, but this was also found to influence the steaming capabilities of the locomotive, as well as suffer the same clogging problems experienced by the other spark arrestor designs.

In 1953 following a fracture on the crank axle of 35020 Bibby Line whilst running at 70mph the whole fleet of Merchant Navy class locomotives was withdrawn from use on the Southern Region until they were rebuilt. During this period the Southern Region was short of motive power and so Standard class Britannias, ex-LMS Class Fives, ex-LNER V2s and B1s, were despatched to both South Western and South Eastern Divisions of the Southern Region. The V2 engines were known to have hauled the Bournemouth Belle and trains east and west of Salisbury.

The B1s did not require any major developments in the design. This was mainly due to the simple, robust nature of the design; but also due to impending conversion to diesel power. The firebox plates did tend to fracture, though. This was sufficiently severe that in 1955 there was a plan to replace the boilers with BR Type 3 boilers, as fitted to the BR Standard Class 5MT locomotives. The heavier boiler would have increased the axle loading and reduced the route availability. By this time, the conversion to diesel power had started and it was decided that it was too late to start a major reboilering programme. Also, the problem with the boilers had been partially solved with the addition of strengthening plates on the firebox flanges.

Number in Service.

Built Withdrawals No. in Service
BR Numbers Quantity
1942 61000



1943 61001-61004



1944 61005-61009



1946 61010-61014 & 61040-61113



1947 61015-61039 & 61114-61273



1948 61274-61339



1949 61340-61359



1950 61360-61373 & 61400-61409




1951 61374-61392



1952 61393-61399





1961       1


1962   120


1963 Including 8 to Service Dept     62


1964 Including 2 to Service Dept     54


1965 Including 4 to Service Dept     81


1966 Including 3 to Service Dept     64


1967     27


Number in Used as Service Locomotives (Additional to the above in service).

Transferred to service Department Withdrawals No. in Service
BR Numbers Quantity
1963 61059,61181,61204,61205,61233,61252,61300 & 61375



1964 61105 & 61323




1965 61138,61194,61264 & 61272




1966 61050,61051 & 61315


7 4






  • Between 1963 and 1966, seventeen of the withdrawn B1s were converted for use as stationary boilers to heat coaching stock. They were renumbered in the Service stock list as 17-32 and they were based at various centres in the Eastern Counties.These had their hooks removed so that they could not pull revenue earning services, but were still capable of moving themselves. All of the stationary boiler B1s were withdrawn by 1968. One of these boilers (61264) was lucky enough to make it to Barry Scrapyard. The only LNER locomotive to reach Barry, 61264 has been restored to running condition.

The first batch of B1s were distributed with eight locomotives in the Great Eastern (GE) Section, and two locomotives in Scotland. As bulk delivery began, early allocations were also given to the Great Central (GC) Section, and to Hitchin to replace the aging Great Northern (GNR) atlantics. By final delivery in 1952, the bulk of the B1s (259 in total) were allocated to BR’s Eastern Region, with 80 and 70 allocated to the North Eastern and Scottish Regions respectively.

In 1953, fourteen B1s were loaned to the Southern Region when the Bulleid Pacifics had to be urgently withdrawn for special axle examinations.

The earliest Great Northern Section B1s operated out of Hitchin, working suburban services to Kings Cross. Due to them being brand new, the B1s were very popular with drivers in the area – even as stand-ins for pacifics and V2s which showed signs of failing. Kings Cross used its B1 allocation to haul the Cambridge buffet expresses which were re-introduced in the late 1940s. The GN also used B1s for fast freight (eg. fish from Hull), and many passenger excursions.

With the arrival of the B1s on the Great Central Section in 1946, they were quickly put to use pulling virtually all of the GC Section passenger expresses, especially those in Lincolnshire and on the London Extension. Most of these services were replaced with diesels and diesel multiple units in the 1950s, leading to the B1s displacing older 0-6-0s on local freight services. The older 0-6-0s were quickly withdrawn. Despite the steady process of dieselisation, the London Extension kept many of its B1s alongside a growing number of Stanier Black 5s and Standard class 5s. Diesel locomotives rarely operated these later years on the London Extension, but some diesel multiple units were used on the southern section between Aylesbury and Marylebone.

The Great Eastern Section experienced a huge increase in traffic during the Second World War. Many of the GE locomotives suffered in their maintenance and hence the arrival of the B1s was much needed and a great success. They quickly started hauling the express passenger workings between Norwich and Liverpool Street. Stratford, March, and Cambridge also received B1s. They quickly became the main passenger locomotive and displaced the B17s. Over time, the GE Section tended to overload the B1s and they would be replaced on the heavier routes by the BR Standard Britannia class pacifics when these arrived in 1951. The B1s would then start to appear on some of the GE Section’s freight services.

The North Eastern Section was responsible for the running-in of the original batch of ten B1s, but these were quickly moved to other regions. It would not receive its own allocation until 1946. The first allocations replaced D49 4-4-0s which Neville Hill was still using for fast services to Newcastle due to the shortage of suitable pacifics. When the pacifics returned, the B1s were allocated to secondary services. Most of the other NE Section B1s were also allocated to passenger services, although B1s at Dairycoates, Borough Gardens, and Stockton worked freight trains. As with the GN Section, the B1 was a popular choice for Saturday excursion trains.

The first two B1s allocated to Scotland were quickly put to work hauling the passenger services on the Edinburgh to Perth main line. Further B1s hauled other passenger services, quickly replacing a variety of 4-4-0 types. B1s allocated to St. Margarets also worked many of the long distance goods trains to Carlisle and Newcastle. The B1s were generally very successful in the Scottish Area and were used for a huge variety of service types. For a number of the GNS (Great North of Scotland) sheds, the B1s were the first mainline locomotives to be delivered new since Grouping in 1923. After Nationalisation in 1948, the B1s would also be regularly seen on former LMS lines in Scotland.

Accidents and Incidents

  • On 7 March 1950, locomotive 61057 was hauling an express passenger train from Peterborough to Liverpool Street at night in dense fog, when it collided with the rear of a mineral train, 3⁄4 mile north east of Witham Junction; the passenger fireman and goods guard were killed. The locomotive was badly damaged; after being moved to Stratford Works, it and its tender were withdrawn and later scrapped. Although B1s were still being built, an extra replacement was not ordered.
  • On 4 September 1953, locomotive 61046 was hauling a passenger train that was derailed at Bethnal Green, London when a set of points moved under it.
  • In August 1961, locomotive 61229 was derailed at Malton, Yorkshire.
61262 Dubdee July 1965.jpg 61262 on Dundee Tay Bridge shed-July 1965.It spent all of its BR working life based in Scotland (Thornton Junction, Dundee Tay bridge & Dunfermline Upper). It was withdrawn from service at Dunfermline Upper in April 1967.
61147 Dundee July 1965.jpg 61147 on Dundee Tay Bridge shed-July 1965. Also a Scottish resident under BR.Withdrawn from service at Dundee Tay Bridge in December 1965 and was scrapped in March 1966.
61293 thornton July 1965.jpg 61293 At Thornton July 1965. This locomotive spent all of its days BR based at Dundee Tay Bridge. It was withdrawn from service in August 1966 and scrapped in December of that year.
61245 Murray of Elibank Dalry Road July 1965.jpg 61245 Murray of Elibank on Dalry Road shed at Edinburgh-July 1965. 61245 spent all of its working life based in Edinburg but managed spells at three sheds – Haymarket, St Margarets & Dalry Road. It was withdrawn from service at Dalry in the same month as I photographed it.
61350 Carlisle August 1965.jpg 61350 at Carlisle-August 1965. Another Scottish based locomotive which started life at Kittybrewster (Aberdeen) before moving further south in 1962. It was withdrawn from service at Dunfermline Upper in November 1966.
61250 York Feb 1966.jpg 61250 A Harold Bibby in the roundhouse that is now the National Railway Museum at York-February 1966.The locomotive was never based at York. It was withdrawn from service at Doncaster inApril 1966.
61388 Low Moor May 1966.jpg 61388 at Low Moor-May 1966. 61388 was based entirely on the North Eastern Region during its life.It was withdrawn from service at Wakefield in January 1967


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