The London & North Eastern Railway Class A2/4 was a class of 4-6-2 steam locomotives designed for express passenger services by Edward Thompson in 1946 to operate on the East Coast Main Line. Only 2 locomotives were constructed and 8 were proposed following Edward Thompson's retirement as CME in 1947. Prior to the introduction of the LNER Class A1/1's, A2/1's, A2/2's, and A2/3's, the A2/4's became a successful pair of engines on the LNER.
Shortly before Thompson's retirement as CME, the LNER was short of express passenger locomotives, so Thompson initiated plans for a new Pacific design, which he intended to be based on the rebuilt No. 113 Great Northern. However, the LNER design office, having received reports of Great Northern's performance in service, delayed completing the design of the locomotive, intended to do so until Thompson had retired. However, Thompson sent the drawings of the A2/4's and it's possible good performance details, trying to convince the LNER design office. After revision on the design, the LNER design office gave greenlit in late November of 1946.
The new Pacific design was to be based on the rebuilt No. 113 Great Northern, with inspiration from the LNER Gresley A4 Class. The A2/4 was made utilizing a front balancing from a Gresley A4, a custom built front footplate, a Walschaerts valve gear, an extended firebox and crew footplate, streamlining fitted ontop of the boiler, and a LNER Gresley Corridor Tender. The result was the Thompson A2/4, with a tractive effort of 43,900lb (195.27 kN), and a top speed of 106 MpH (171 km/h), both built at Doncaster Works in December of 1946.
Originally, the design was made as a de-streamlining for the A2/3's to increase their performance, but the short on express passenger locomotives notice led Thompson to build these locomotives. The A2/4's were originally going to be numbered 500-509, however the A2/1's and A2/3's took some of the numbers, having the A2/4's numbers changed to 5000-5009. Only 2 A2/4's were built, No. 5000 Duchess of Royalty, and No. 5001 Duchess of Newcastle, with the remainder being proposed in favour of the Peppercorn A2's in 1947.
Both A2/4's had a good performance on the East Coast Main Line, although they suffered from 'the long spacing between the bogie and the leading coupled wheels, resulting in undue flexing of the frames and constant troubles from the outside pipe connections to the valve chests.' like the A2/3's. They also often consumed large amounts of coal, especially at high speeds. Despite these problems, the A2/4's were successful locomotives, being in service until 1966 when they were placed by BR Class 53's.
Both examples survived into preservation, being preserved at the National Railway Museum at York as static display. As of 2022, they're both planned to be Mainline certified.
The A2/4 Class fleet is listed below, including the proposed locomotives:
5000: Duchess of Royalty
5001: Duchess of Newcastle
5002: Duchess of Sheffield
5003: Great Central
5004: Great Eastern
5005: North Eastern
5006: North British
5007: Duchess of York
5008: Duchess of London
5009: Duchess of Edinburgh
Concept of No. 500 Edward Thompson in de-streamlined condition.
Shortly before Thompson's retirement as CME, the LNER was short of express passenger locomotives, so Thompson initiated plans for a new Pacific design, which he intended to be based on the rebuilt No. 113 Great Northern. However, the LNER design office, having received reports of Great Northern's performance in service, delayed completing the design of the locomotive, intended to do so until Thompson had retired. However, Thompson sent the drawings of the A2/4's and it's possible good performance details, trying to convince the LNER design office. After revision on the design, the LNER design office gave greenlit in late November of 1946.
The new Pacific design was to be based on the rebuilt No. 113 Great Northern, with inspiration from the LNER Gresley A4 Class. The A2/4 was made utilizing a front balancing from a Gresley A4, a custom built front footplate, a Walschaerts valve gear, an extended firebox and crew footplate, streamlining fitted ontop of the boiler, and a LNER Gresley Corridor Tender. The result was the Thompson A2/4, with a tractive effort of 43,900lb (195.27 kN), and a top speed of 106 MpH (171 km/h), both built at Doncaster Works in December of 1946.
Originally, the design was made as a de-streamlining for the A2/3's to increase their performance, but the short on express passenger locomotives notice led Thompson to build these locomotives. The A2/4's were originally going to be numbered 500-509, however the A2/1's and A2/3's took some of the numbers, having the A2/4's numbers changed to 5000-5009. Only 2 A2/4's were built, No. 5000 Duchess of Royalty, and No. 5001 Duchess of Newcastle, with the remainder being proposed in favour of the Peppercorn A2's in 1947.
Both A2/4's had a good performance on the East Coast Main Line, although they suffered from 'the long spacing between the bogie and the leading coupled wheels, resulting in undue flexing of the frames and constant troubles from the outside pipe connections to the valve chests.' like the A2/3's. They also often consumed large amounts of coal, especially at high speeds. Despite these problems, the A2/4's were successful locomotives, being in service until 1966 when they were placed by BR Class 53's.
Both examples survived into preservation, being preserved at the National Railway Museum at York as static display. As of 2022, they're both planned to be Mainline certified.
The A2/4 Class fleet is listed below, including the proposed locomotives:
5000: Duchess of Royalty
5001: Duchess of Newcastle
5002: Duchess of Sheffield
5003: Great Central
5004: Great Eastern
5005: North Eastern
5006: North British
5007: Duchess of York
5008: Duchess of London
5009: Duchess of Edinburgh
Concept of No. 500 Edward Thompson in de-streamlined condition.