Data from "Passenger Locomotive for the Barry Dock & Railway Company", Engineering, Volume 55 (30 June 1893), p. 902; and and "Barry Railway", The Locomotive Magazine, Volume XXIX [29] (15 February 1923), p. 36-39. Vulcan works number were 1348-1349 in August 1892. Sharp, Stewart added two more in March 1895.
According to Engineering at the time the Barry Railway ordered the first pair of four-coupled bogie tanks in 1892, its passenger route covered just 5 3/4 miles (9.25 km) between Barry and Cogan. Its service demanded both relatively high speeds and frequent stops, so the engine had to offer acceleration and braking power in equal measure.
A few months after delivery, the Engineering reported that the engines had worked "very satisfactorily". Each was pulling a tare trailing load of 150 tons in 10-12 six-wheel carriages over a providle that included a 0.5 grade rising over 60% of the line's length. Coal consumption averaged 31.52 lb/mile (8.89 kg/km) to heat 30.86 Imperial gallons (37 US gallons) per mile (19.17 Imp gal or 23 US gallons/km).
In 1922, when the Barry was taken into the Great Western as part of the Grouping, all four locomotives remained in service and were given new (and very low) road numbers.
| Principal Dimensions by Steve Llanso of Middle Run Media | |
|---|---|
| Class | G |
| Locobase ID | 20526 |
| Railroad | Barry |
| Country | Great Britain |
| Whyte | 0-4-4T |
| Number in Class | 2 |
| Road Numbers | 66-69/2-4, 9 |
| Gauge | Std |
| Number Built | 2 |
| Builder | Vulcan Foundry |
| Year | 1892 |
| Valve Gear | Stephenson |
| Locomotive Length and Weight | |
| Driver Wheelbase (ft / m) | 7.42 / 2.26 |
| Engine Wheelbase (ft / m) | 21.50 / 6.55 |
| Ratio of driving wheelbase to overall engine wheelbase | 0.35 |
| Overall Wheelbase (engine & tender) (ft / m) | 21.50 / 6.55 |
| Axle Loading (Maximum Weight per Axle) (lbs / kg) | |
| Weight on Drivers (lbs / kg) | |
| Engine Weight (lbs / kg) | 125,552 / 56,949 |
| Tender Loaded Weight (lbs / kg) | |
| Total Engine and Tender Weight (lbs / kg) | 125,552 / 56,949 |
| Tender Water Capacity (gals / ML) | 1680 / 6.36 |
| Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT) | 1.65 / 2 |
| Minimum weight of rail (calculated) (lb/yd / kg/m) | |
| Geometry Relating to Tractive Effort | |
| Driver Diameter (in / mm) | 67.50 / 1715 |
| Boiler Pressure (psi / kPa) | 150 / 1030 |
| High Pressure Cylinders (dia x stroke) (in / mm) | 18" x 26" / 457x660 |
| Tractive Effort (lbs / kg) | 15,912 / 7217.57 |
| Factor of Adhesion (Weight on Drivers/Tractive Effort) | |
| Heating Ability | |
| Tubes (number - dia) (in / mm) | 181 - 2" / 51 |
| Flues (number - dia) (in / mm) | |
| Flue/Tube length (ft / m) | 10.79 / 3.29 |
| Firebox Area (sq ft / m2) | 110 / 10.22 |
| Grate Area (sq ft / m2) | 20.75 / 1.93 |
| Evaporative Heating Surface (sq ft / m2) | 1133 / 105.26 |
| Superheating Surface (sq ft / m2) | |
| Combined Heating Surface (sq ft / m2) | 1133 / 105.26 |
| Evaporative Heating Surface/Cylinder Volume | 147.96 |
| Computations Relating to Power Output (More Information) | |
| Robert LeMassena's Power Computation | 3113 |
| Same as above plus superheater percentage | 3113 |
| Same as above but substitute firebox area for grate area | 16,500 |
| Power L1 | 3709 |
| Power MT | |