The 4600 Class was a 4-4-2T steam locomotive built by the Great Western Railway in 1913. It was one of the GWR standard classes with two outside cylinders.

GWR 4600 Class
GWR 4-4-2T No. 4600
Type and origin Power type Steam Designer George Jackson Churchward Builder GWR Swindon Works Order number Lot 197 Serial number 2551 Build date 1913 Total produced 1
Specifications Configuration: ​  • Whyte 4-4-2T Gauge 4 ft 8+1⁄2 in (1,435 mm) standard gauge Leading dia. 3 ft 2 in (0.965 m) Driver dia. 5 ft 8 in (1.727 m) Trailing dia. 3 ft 2 in (0.965 m) Length 36 ft 11+3⁄4 in (11.271 m) Loco weight 60 long tons 12 cwt (61.6 t; 67.9 short tons) Fuel type Coal Fuel capacity 3 long tons (3.0 t; 3.4 short tons) Water cap. 1,100 imp gal (5,000 L; 1,300 US gal) Firebox: ​  • Type Belpaire  • Grate area 93.85 sq ft (8.719 m2) Boiler GWR Standard No. 5[1] Boiler pressure 200 psi (1.4 MPa) Cylinders Two, outside Cylinder size 17 in × 24 in (432 mm × 610 mm)
Performance figures Tractive effort 18,360 lbf (81.7 kN)
Career Operators Great Western Railway Class 4600 Power class GWR: A Axle load class GWR: Blue Withdrawn 1925 Disposition Scrapped

It was designed as light suburban locomotive, based on the successful 4500 class 2-6-2T engines. Compared with these, it had larger (and fewer) coupled wheels, intended to allow higher speeds with local trains. The only example built spent most of its career in the Birmingham area, and was not considered a success. The limited adhesion and restricted tank capacity meant that it did not improve on the 4500 class, and the larger 2-6-2T classes handled the suburban traffic better. It was moved to western Wales in 1918 for use on the lines to Pembroke Dock and Neyland. It was withdrawn in 1925 and scrapped.^[2][3][4]