| GER Class D81 LNER Class J20 | |
| Powertype: | Steam |
| Designer: | A. J. Hill |
| Builder: | Stratford Works |
| Builddate: | 1920 - 1922 |
| Totalproduction: | 25 |
| Whytetype: | 0-6-0 |
| Uicclass: | C h2 |
| Driverdiameter: | 4feet |
| Wheelbase: | 40feet |
| Length: | 54feet over buffers |
| Fueltype: | Coal |
| Boilerpressure: | 1802NaN2 |
| Firearea: | 26.5square feet |
| Totalsurface: | 1834.2square feet |
| Cylindercount: | Two, inside |
| Cylindersize: | 20x |
| Tractiveeffort: | 290442NaN2 |
| Powerclass: | BR: 5F |
| Axleloadclass: | LNER/BR: RA 5 |
| Withdrawndate: | 1959–1962 |
| Disposition: | All scrapped |
The GER Class D81 was a class of twenty-five 0-6-0 steam locomotives designed by A. J. Hill for the Great Eastern Railway. The all passed to the London and North Eastern Railway at the 1923 grouping and received the classification J20.
These locomotives were fitted with 20x cylinders and 4feet wheels, while the Belpaire firebox-fitted boiler was identical to that fitted to the Class S69 4-6-0s. They were the most powerful 0-6-0 tender locomotive in Britain until the arrival of Oliver Bulleid's Q1 class for the Southern Railway in 1942.
| 1920 | D81 | 5 | 1270–1274 | 8270–8274 | 4675–4679 | ||
| 1922 | M87 | 10 | 1275–1284 | 8275–8284 | 4680–4689 | ||
| 1922 | Y87 | 10 | 1285–1294 | 8285–8294 | 4690–4699 | ||
All were still in service at the 1923 grouping, the LNER adding 7000 to the numbers of nearly all the ex-Great Eastern locomotives, including the Class D81 locomotives. Between 1943 and 1956 the class was rebuilt with round-top fireboxes, and reclassified as J20/1.
At nationalisation in 1948, British Railways added 60000 to their LNER numbers. They all continued in service until 1959, when the first was withdrawn; all were gone by the end of 1962.
| Year | Quantity in service at start of year | Quantity withdrawn | Locomotive numbers | Notes |
|---|---|---|---|---|
| 1959 | 25 | 3 | 64675/83/88 | |
| 1960 | 22 | 9 | 64678/81–82/84–86/93–95 | |
| 1961 | 13 | 8 | 64676–77/79–80/89/92/97–98 | |
| 1962 | 5 | 5 | 64687/90–91/96/99 | |