| Power Classification | 3MT |
| Introduced | 1954 |
| Designer | Riddles, designed at Swindon |
| Company | BR |
| Weight – Loco | 57t 9cwt |
| Tender | 42t 3cwt |
| Driving Wheels | 5ft 3ins |
| Boiler Pressure | 200psi superheated |
| Cylinders | Outside – 17½6n x 26in |
| Tractive Effort | 21,490lbf |
| Valve Gear | Walschaert (piston valve) |
These locomotives were built as a tender version of the 82000 3MT class, designed for working on virtually any main or secondary line throughout Britain. They had a boiler based on the GWR Swindon boiler fitted to the GWR 5101 and 5600 class locomotives. The chassis were closely based on and sharing a number of parts with the LMS Ivatt 43000 class 4.
 | 77000 class introduced in 1954 |
 | LMS 43000 class designed by Ivatt introduced in 1947 |
 | 82000 class introduced in 1952 |
 | GWR 5101 class designed by Churchward introduced in 1903 |
 | GWR 5600 class designed by Collett introduced in 1924 |
Both the tender version (77000 class) and tank version (82000 class) were all built at Swindon. The tank engine version was introduced in April 1952 whilst the first tender engines was completed in February 1954. The tank engines were more numerous with 45 being built compared to only 20 of the tender engines. There had been plans to build a further five members of the 77000 class engines but the order was later cancelled.
Unlike a number of the larger BR Standards the exhaust steam manifold within the smokebox saddle was a steel fabrication that was part of the welded saddle. In a number of the large BR standards (BR Standard class 6 and class 7 engines) the exhaust steam manifold was a steel casting welded into the saddle during manufacture.
They were fitted with BR2A 3,500 gallon tenders.
Number in Service.
| Built | Withdrawals |
No. in Service | |
| 1954 |
20 |
20 | |
| 1955-64 |
20 | ||
| 1965 |
1 |
19 | |
| 1966 |
16 |
3 | |
| 1967 |
3 |
0 |
Allocation of locomotives in service as at 1st of January.
|
Depot byRegion | 1955 | 1958 | 1962 | 1964 | 1965 | 1966 |
1967 |
| North Eastern | |||||||
| Blaydon |
2 | ||||||
|
Darlington |
3 | 1 |
1 | ||||
| Farnley Junction |
2 | ||||||
| Goole |
1 | ||||||
| Hull Botanical Gardens |
2 | ||||||
| Hull Dairycoates | 3 |
1 | |||||
| Hull Springhead |
1 | ||||||
| Manningham |
2 | ||||||
| Scarborough |
2 | ||||||
| South Byth |
2 | ||||||
| Stourton | 5 | 4 |
3 | ||||
| Tweedmouth | 2 |
2 | |||||
| West Auckland |
7 | 2 | 2 |
2 | |||
| Whitby |
2 | ||||||
| York | 1 |
2 | |||||
|
10 | 10 | 10 | 10 | 8 | 7 |
2 | |
| Scottish | |||||||
| Carstairs |
1 | ||||||
| Grangemouth | 2 |
2 | |||||
| Hamilton |
3 | 3 |
1 | ||||
| Hurlford |
5 | 5 | 5 | 6 | 6 |
6 | |
| Motherwell | 2 | 2 |
4 | ||||
| Polmadie |
2 | 2 |
3 | ||||
|
10 | 10 | 10 | 10 | 10 |
10 | ||
| London Midland | |||||||
| Northwich | 2 |
2 | |||||
| Southern | |||||||
| Guildford |
1 | ||||||
|
20 | 20 | 20 | 20 | 20 | 19 |
3 |
77014 ended its working life at Guildford in July 1967 having previously been based at North Eastern and London Midland Region depots as set out below. It was the last steam locomotive in use on the Southern Region on 9th July 1967.
| Date Arrived | Depot |
| July 1954 | Darlington |
| October 1955 | Whitby |
| June 1956 | Blaydon |
| October 1959 | Gateshead |
| September 1960 | Tyne Dock |
| April 1961 | South Blyth |
| October 1962 | Thornaby |
| September 1963 | Stourton |
| November 1964 | Northwich |
| April 1966 | Guildford |
The tank engine version (82000 class) were initially mainly based at Western Region (27) and Southern Region (14) depots with a few (4) starting life on the North Eastern Region. Some of the Western Region locomotives moved to the London Midland Region when the control of Machynlleth depot was transferred in September 1963.
  | 77013 at Stourton-May 1966. This locomotive spent all of its working life on the North Eastern Region. It entered service at Darlington in July 1954 before moving on to Whitby, Leeds Neville Hill, Selby, York, Scarborough and York again before going to Stourton in September 1963. It was withdrawn from service there in March 1966. |
 | 77000 & 77003 at Stourton-July 1966. These two were always based on the North Eastern Region and ended up at Stourton in 1964.They were both withdrawn from service in December 1966. Stourton shed closed in January 1967. |
 | 77004 with 43004 at Stourton-July 1966. 77004 was based at ten North Easter Region sheds during its 12 year life. |
 | 77018 with 45274 at Hurlford-July 1966. 77018 was based at Hurlford for all of its twelve years of service. It was withdrawn from service in November 1966. |
 | 77017 Kilmarnock-July 1966. This locomotive was based at Hurlford for all of its working life which lasted from August 1954 until November 1966. |
New Build
None of the 20 locomotives which operated on BR metal have been preserved although some components were removed from engines whilst at scrapyards to build a new Standard class 3 2-6-2T.
