Barry Railway Class B1 were 0-6-2T steam tank locomotives of the Barry Railway in South Wales. They were designed by J. H. Hosgood and built by Sharp Stewart, & Co., Vulcan Foundry and Société Franco-Belge.^[1] The locomotive, though similar to the B class, differed in having an increased tank capacity of 1,630 gallons compared with the 1,400 gallons of the B class. The purpose of this was to enable them to take a train of empty wagons from Cadoxton Yard to Trehafod Junction without the need to refill the tank.

Barry Railway Class B1
Former Barry Railway Class B1 0-6-2T at Swindon in 1950, British Railways no. 269
Type and origin Power type Steam Designer J. H. Hosgood Builder Sharp, Stewart & Co. (27), Vulcan Foundry (10), Société Franco-Belge (5) Build date 1890–1900 Total produced 42 Number rebuilt Some rebuilt from 1924 with GWR boiler
Specifications Configuration: ​  • Whyte 0-6-2T  • UIC C1 n2t Gauge 4 ft 8+1⁄2 in (1,435 mm) standard gauge Driver dia. 4 ft 4 in (1.321 m); Rebuilds: 4 ft 3 in (1.295 m) Trailing dia. 3 ft 6 in (1.067 m) Loco weight 55 long tons 3 cwt (123,500 lb or 56 t) (61.8 short tons); Rebuilds: 53 long tons 9 cwt (119,700 lb or 54.3 t) (59.9 short tons) Fuel type Coal Boiler pressure 160 psi (1.10 MPa); Rebuilds: 150 psi (1.03 MPa) Heating surface: ​  • Tubes 1.875 in (0.048 m) Superheater: ​  • Heating area 1,070 sq ft (99.406 m2) Cylinders Two Inside Cylinder size 17.5 in × 26 in (444 mm × 660 mm) Valve gear Stephenson
Performance figures Tractive effort 20,825 lbf (92.63 kN); Rebuilds: 19,906 lbf (88.55 kN)
Career Operators BR » GWR » BR Withdrawn 1932–1951 Disposition All scrapped

Their main duty was to take loaded coal trains from Trehafod Junction, and the pits on the Brecon & Merthyr, to Cadoxton Yard and return either with the empty wagons or occasionally pit props from Barry Docks. However they could also be seen pulling colliers' trains between Barry and Porth as well as excursion trains from various locations to Barry Island. In particular 2 B1 class locomotives, nos. 111 and 122, were used to take excursion trains from the Rhymney Railway to Barry for those visiting the National Eisteddfod held there in 1920. B1s could also be seen pulling the 'Ports Express' from Barry to Newcastle over the Barry Railway section of the journey between Barry and Cardiff.

The locomotives passed to the Great Western Railway in 1922 and 20 survived into British Railways ownership in 1948. However, all 20 had been withdrawn by 1952 and none were preserved.