| LNER Thompson Class B2 | |
| Powertype: | Steam |
| Designer: | Edward Thompson |
| Builddate: | 1928–1937 (as class B17) |
| Rebuilder: | Doncaster Works |
| Rebuilddate: | 1945–1949 |
| Numberrebuilt: | 10 |
| Whytetype: | 4-6-0 |
| Uicclass: | 2′C h2 |
| Leadingdiameter: | 3feet |
| Driverdiameter: | 6feet |
| Wheelbase: | Loco: 28feet |
| Axleload: | Full: |
| Weightondrivers: | Full: |
| Locoweight: | Full: |
| Fueltype: | Coal |
| Boiler: | Diagram 100A |
| Boilerpressure: | 225psi |
| Firearea: | 27.9square feet |
| Tubearea: | 1033square feet |
| Fluearea: | 460square feet |
| Fireboxarea: | 168square feet |
| Superheaterarea: | 344square feet |
| Cylindercount: | Two, outside |
| Cylindersize: | 20inchesx26inchesin (xin) |
| Valvegear: | Walschaerts |
| Valvetype: | 10inches piston valves |
| Tractiveeffort: | 24863lbf |
| Operator: | LNER » BR |
| Operatorclass: | B2 |
| Powerclass: | LNER: load class 4 BR: 4P; 5P from May 1953 |
| Axleloadclass: | Route availability 5 |
| Locale: | East Coast Main Line |
| Withdrawndate: | 1958–1959 |
| Disposition: | All scrapped |
The London and North Eastern Railway (LNER) Thompson Class B2 was a class of 4-6-0 steam locomotive. It was introduced in 1945 as a two-cylinder rebuild (with diagram 100A boiler) of the three-cylinder LNER Class B17. Ten were rebuilt from Class B17 but no more were rebuilt because of the success of the LNER Thompson Class B1.
The LNER renumbered its locomotive stock during the period that these locomotives were being rebuilt, so some were renumbered at the time that they were rebuilt, some before rebuilding, and some after rebuilding. The renumbering plan for class B2 was the same as for class B17: in each case the first two digits were altered from 28 to 16. Thus 2803 became 1603 at rebuilding in October 1946; 2807 had already become 1607 (December 1946) prior to rebuilding in May 1947; and 2814 (rebuilt November 1946) became 1614 in December 1946. Between 1948 and 1950, British Railways increased these numbers by 60000; no. 61644 was so renumbered at the time of its rebuilding in March 1949.
The rebuilt locomotives kept their names:
Two of the locomotives were renamed. No. 1671 was the official Royal engine and for this purpose it was renamed Royal Sovereign in April 1946.
The second renaming occurred after the withdrawal of 61671 in September 1958: in October, the name Royal Sovereign was transferred to no. 61632, which then became the official Royal engine. All members of the class were scrapped.
Two B2s were kept at for hauling the Royal Train in East Anglia, predominantly to and from which was the nearest to Sandringham House, these being renamed Royal Sovereign and 61617 Ford Castle as the reserve. There were three sets of drivers and firemen allocated specifically to work the "Royal" engines and they did not work unless operated by one of these teams. It was Ford Castle which was one of the locomotives used to haul the funeral train of King George VI on 11 February 1952, hauling the train from Wolferton as far as from where 70000 Britannia took over for the rest of the journey to King's Cross.
Other than the two locomotives allocated to Cambridge, the remaining locomotives were mainly allocated to Colchester and were predominantly used on services between Liverpool Street and Clacton. Many publications list "B17/B2" together and consider the types interchangeable which may lead to the type being overlooked; a list of locomotives allocated to Colchester in 1951 and labelled as "B2/B17" shows eight B2s and no B17s.
Due to the size of the turntables on the Great Eastern section, locomotives were sometimes used with tenders that were shorter than those originally designed. At least one B2 was recorded as being paired with a tender of NER origin rather than the longer B17 tender.[1]
The last B2 was withdrawn in 1959.[2]