Drummond D50 (NBR Class P) 4-4-0T Tank Engines

Drummond D50 (NBR Class P) 4-4-0T, at Balloch

Drummond adopted Wheatley's leading bogie design and successfully used it on his "Abbotsford" 4-4-0 Class. For operating the passenger services along the Clyde Coast, Drummond chose a 4-4-0T using the same bogie design to replace his own 0-4-2Ts which were then operating these services. Three of these locomotives were built in 1879 by Neilson & Co. No further D50s were built, although Drummond did build the smaller D51 4-4-0T in greater numbers.

The only significant change experienced by the D50s, was the fitting of G8 boilers by Reid in 1905.

Initially, the D50 class worked the trains between Glasgow and Helensburgh before being replaced by Reid's C15 4-4-2T tank engines in 1913. They then moved to Dundee, Eastfield, and Parkhead. By Grouping in 1923, No. 1390 was based at Fort William. No. 1392 was withdrawn from branch work out of Bathgate, in 1924. The last two remained in service until 1926.

Technical Details

The following details describe the D50s when they entered LNER ownership. They were originally built with 140psi boilers.

Cylinders (x2): 17x24in.
Motion: Stephenson slide valves
Boiler: Max. Diameter: 4ft 5in
Pressure: 150psi
Heating Surface: Total: 1051.4 sq.ft.
Firebox: 101.4 sq.ft.
Tubes: 950 sq.ft. (200x 1.75in)
Grate Area: 16.5 sq.ft.
Wheels: Leading: 3ft 6in
Coupled: 6ft
Tractive Effort: 13,305lb (@ 85% boiler pressure)
Total Wheelbase: 21ft 1in
Engine Weight: 47 tons 4cwt (full)
Max. Axle Load: 16 tons 14cwt
Coal Capacity: 1 ton 11cwt
Water Capacity: 950 gallons


The last two D50s were withdrawn in 1925 and none survived into preservation.


I am not aware of any models of the D50s in any scale.


All three members of the D50 class were named. At Grouping they were allocated numbers 9231, 9232, and 9268; but the first two only bore these numbers for a few months. No. 1392 never received an LNER number before it was withdrawn.

1st NBR No.2nd NBR No.LNER No.Disposal DateName