NBR J Class LNER Classes D29 & D30
Type and origin Power type Steam Designer William P. Reid Builder North British Locomotive Company and NBR Cowlairs Works Build date 1909-1920 Total produced 43 locomotives (16 type D29 & 27 type D30)
Specifications Configuration: ​  • Whyte 4-4-0 Gauge 4 ft 8+1⁄2 in (1,435 mm) Leading dia. 3 ft 6 in (1.07 m) Driver dia. 6 ft 6 in (1.98 m) Length 46 ft 8.5 in (14.24 m) Axle load 18.4 long tons (18.7 t) Loco weight 54.8 long tons (55.7 t) D29, 57.3 long tons (58.2 t) D30/1, 57.8 long tons (58.7 t) D30/2 Tender weight 46.0 long tons (46.7 t) Fuel type coal Firebox: ​  • Grate area 21.13 square feet (1.963 m2) Boiler 5 ft 0 in (1.52 m) diameter Boiler pressure 190 psi (1.3 MPa) D29, 165 psi (1.14 MPa) D30 Heating surface: ​  • Firebox 139.7 square feet (12.98 m2)  • Tubes 1,478.3 square feet (137.34 m2) D29, 871.3 square feet (80.95 m2) D30/1 677.0 square feet (62.90 m2) D30/2 Cylinders 2 Cylinder size 19 in × 26 in (480 mm × 660 mm) D29, 20 in × 26 in (510 mm × 660 mm) D30 Valve gear Stephenson
Performance figures Tractive effort 19,434 lbf (86.45 kN) D29 18,700 lbf (83 kN) D30
Career Operators NBR, LNER, BR Class NBR J; LNER D29 and D30 Power class BR: 3P Numbers 243-245, 338-340, 359-363, 400, 409-428, 497-501, 895-899, 990 Nicknames Scott class Retired 1945-1960 Disposition All engines scrapped

The NBR J Class (LNER Classes D29 & D30), commonly known as the Scott class, were a class of 4-4-0 steam tender locomotives designed by William P. Reid for the North British Railway. They passed to the London and North Eastern Railway at the grouping in 1923. Forty-three were built, of which thirty-five (ten D29s and twenty-five D30s) survived into British Railways ownership in 1948.

The original J Class locomotives were based on the NBR K Class mixed traffic 4-4-0s. The J Class had 6' 6" driving wheels for express passenger work and a large tender which carried sufficient water to allow passenger trains to run non-stop between Edinburgh and Carlisle. These locomotives were named after characters in the novels of Sir Walter Scott and naturally became known as "Scotts". Some of the names were later re-used on LNER Peppercorn Class A1 locomotives.

Six locomotives were built in 1909 by the North British Locomotive Company and a further ten were built in 1911 by the North British Railway at its Cowlairs railway works, followed by two further identical locomotives with superheaters.^[1] The NBR always referred to these locomotives as J Class, but the LNER classified the initial 16 locomotives D29, and the two superheated locomotives as D30.^[2] A further 25 superheated locomotives were built between 1914 and 1920 and the LNER classified these as D30/2.^[3]

• On 3 January 1917, locomotive No. 421 Jingling Geordie overran signals and was in a head-on collision with an express passenger train at Ratho, Lothian. 12 people were killed and 44 were seriously injured. Irregular operating procedures were a major contributory factor in the accident. These were subsequently stopped.^[4]

• On 10 December 1937, No. 9896 Dandie Dinmont was hauling a Dundee to Glasgow Queen Street express train when it was involved in an accident at Castlecary, North Lanarkshire. The train was running late in whiteout conditions when it overran a red home signal at Castlecary. Thankfully, there was no collision with the freight train at Dullatur East, but believing that the train was entering the next section, the signalman sent another express train, hauled by LNER Class A3 4-6-2 No. 2744 Grand Parade, into the section. Minutes later, Grand Parade plowed into the back of the first express. 35 people were killed and another 179 people were injured. ^[5][6][7][8]

British Railways numbers^[9] were:

• D29, 62401-62413 (with gaps)
• D30, 62417-62442 (62433 missing)

NBR no. 898 was named after Sir Walter Scott the author of the Waverley Novels, and the others were given the names either of those novels, or of characters and places in them. The LNER increased the NBR numbers by 9000, and these were applied between 1924 and 1926. New LNER numbers were allotted in 1943 in the order of construction, but the locos were not renumbered until 1946, by which time two had been withdrawn. British Railways increased the LNER 1946 numbers by 60000 between 1948 and 1950, but some were withdrawn before this could be carried out. Numbers in parentheses were allocated but not carried.^[10]