DW&WR 55
Type and origin Power type Steam Designer Grierson Builder Vulcan Foundry Serial number 1448/49, 1455/56 Build date 1895–1896 Total produced 4 Rebuilder Grand Canal Street Rebuild date 1906–1923 Number rebuilt 4
Specifications Configuration: ​  • Whyte 4-4-0 Gauge 5 ft 3 in (1,600 mm) Leading dia. 3 ft 3 in (990 mm) Driver dia. 6 ft 1 in (1,850 mm) Length 34 ft (10,000 mm) (est.) Axle load 15 long tons (15 t) Loco weight 43.75 long tons (44.45 t) Water cap. 2,600 imp gal (12,000 L; 3,100 US gal) Boiler pressure 160 lbf/in2 (1.10 MPa) Cylinders Two Cylinder size 18 in × 26 in (457 mm × 660 mm)
Performance figures Tractive effort 15,700 lbf (69.84 kN)
Career Operators DW&WR DSER GSR Class D9 (Inchicore) Power class N/M Numbers DWWR/DSER: 55–58 GSR: 450–453 Locale Ireland Withdrawn 1929-1940 Disposition All scrapped
Details are for No. 56 after 1911 rebuild[1]

Dublin, Wicklow and Wexford Railway (DW&WR) 55 to 58 were 4-4-0 locomotives built from 1895 at Vulcan Foundry for express passenger duties on the Dublin—Wexford mainline. They were to remain the DW&WR's and subsequent Dublin and South Eastern Railway's leading express passenger locomotive until the arrival of Nos. 67 and 68 some ten years later.

These 4-4-0 locomotives built from 1895 at Vulcan Foundry and named Rathdown, Rathmines, Rathnew and Rathdrum.^[1] In their initial form they were poor steamers, the suggestion being the locomotive superintendent Grierson had specified larger cylinders on a previous design for an English railway without balancing this with an increased boiler. His successor Cronin rebuilt the locomotives with Belpaire boilers resulting in improved performance. On amalgamation to Great Southern Railways in 1925 they became numbered 450 to 453 and allocated to class 450/D8.^{[Note 1]} They were withdrawn between 1939 and 1940.^[1]

These engines took over the express passenger trains from the smaller 2-4-0 type on the DW&WR's Dublin—Wexford mainline route.^{[Note 2][2]}