The Cowan D45 (GNSR Class M) 4-4-0 Locomotives

D30/2 No. 9497 'Peter Poundtext' at Eastfield shed in about 1928

The Great North of Scotland Railway (GNSR) ordered twelve locomotives in 1877 based on Cowan's earlier GNSR Class L (LNER D47/1) locomotives but with larger diameter cylinders (17.5in compared to 17in). The design followed the traditional GNSR outside cylinder 4-4-0 pattern. Three of the locomotives were fitted with 6ft 1in driving wheels and became GNSR Class C (LNER D39). The remaining nine locomotives were fitted with 5ft 7in driving wheels and became GNSR Class M (LNER D45). The D45s also differed from the earlier D47/1s due to a cab sidesheet that neatly curved into the rear splasher. The D47/1 was fitted with a box splasher. All nine engines were built by Neilson & Co, and they were delivered between August and November 1978.

Pickersgill fitted larger 4ft 6in diameters boilers to the class between 1896 and 1904. The boilers were built by a number of different contractors. Records are scarce, but Kitson & Co are known to have supplied three of them. Much of Cowan's ornate beading and brass ornament was removed during the re-boilering. The original boilers had Salter safety valves fitted to the dome, but these were replaced by Ramsbottom valves mounted directly on the firebox. The LNER later fitted standard Ross pop valves to No. 6840 (GNSR No. 40).

The D45s were initially allocated to general duties on the main line between Aberdeen, Keith, and Elgin. Over time, they were displaced from these duties to passenger and goods branch line workings. By Grouping (1923), Nos. 58 & 62 were allocated to Elgin. The remaining seven engines were allocated to Kittybrewster, although they could often be found at Kittybrewster sub-sheds (e.g.. Macduff). As well as branch line duties, the D45s were also being used for shunting. Eight of the D45s were withdrawn between 1925 and 1927. The exception was No. 6840 which remained at Kittybrewster as a spare locomotive until it was finally withdrawn in 1932.

Technical Details

Cylinders (x2): (inside) 17.5x26in.
Motion: Stephenson
Valves: slide
Boiler: Max. Diameter: 4ft 6in
Boiler: Pressure: 150psi
Heating Surface: Total: 1118.5 sq.ft.
Firebox: 100 sq.ft.
Tubes: 1018.5 sq.ft. (215x 1.75in)
Grate Area: 15.64 sq.ft.
Wheels: Leading: 3ft 0.5in
Coupled: 5ft 7in
Tender: 3ft 7.5in
Tractive Effort: (@ 85% boiler pressure) 15,152 lb
Wheelbase: Total: 39ft 3.5in
Engine: 20ft 6.5in
Tender: 11ft 0in
Weight (full): Total: 71 tons 4cwt
Engine: 42 tons 4cwt
Tender: 29 tons 0cwt
Adhesive Weight: 27 tons 10cwt
Max. Axle Load: 14 tons 4cwt


The last D45 was withdrawn in 1932, and none have survived into preservation.


I am not aware of any models of the D45 in any scale.