SEK Class Θβ

SEK (Sidirodromoi Ellinikou Kratous, Hellenic State Railways) Class Θβ (or Class THb; Theta-beta) is a class of two 2-8-0 steam locomotives acquired after the First World War.

SEK class Θβ
Type and origin Power type Steam Builder Henschel & Sohn Build date 1912
Specifications Configuration: ​  • Whyte 2-8-0  • UIC 1′D n4v Gauge 1,435 mm (4 ft 8+1⁄2 in) Leading dia. 850 mm (2 ft 9+1⁄2 in) Driver dia. 1,450 mm (4 ft 9+1⁄8 in) Length 17,905 mm (58 ft 9 in) Height 4,650 mm (15 ft 3+1⁄16 in) Axle load 14.15 tonnes (13.93 long tons; 15.60 short tons) Adhesive weight 56.60 tonnes (55.71 long tons; 62.39 short tons) Loco weight 69.97 tonnes (68.86 long tons; 77.13 short tons) Total weight 115.17 tonnes (113.35 long tons; 126.95 short tons) Fuel type Coal Fuel capacity 8 tonnes (7.9 long tons; 8.8 short tons) Water cap. 18,600 litres (4,100 imp gal; 4,900 US gal) Firebox: ​  • Grate area 3.96 m2 (42.6 sq ft) Boiler pressure 15 kg/cm2 (1.47 MPa; 213 psi) Heating surface: ​  • Tubes 213.0 m2 (2,293 sq ft)  • Total surface 226.7 m2 (2,440 sq ft) Cylinders Four, compound High-pressure cylinder 400 mm × 650 mm (15+3⁄4 in × 25+9⁄16 in) Low-pressure cylinder 640 mm × 650 mm (25+3⁄16 in × 25+9⁄16 in)
Performance figures Maximum speed 80 km/h (50 mph)
Career Operators BDŽ → SEK → BŽD Numbers BDŽ 806/811 → SEK 621/622 → SEK 521/522 → BŽD 17.72/17.73

Originally one of the Bulgarian State Railways' (BDŽ) 800 series four-cylinder compound locomotives that had been built by Henschel & Sohn in 1912 as BDŽ 806 and 811. They were given the class letters "Θβ" by the SEK and initially numbered 621 and 622 before being renumbered 521 and 522.

During World War II, they were reclaimed by the Bulgarians and renumbered BDŽ 17.72 and 17.73 at the end of the surviving 800s (which by then had become BDŽ class 17).

References

• Durrant, A. E. (1972). The Steam Locomotives of Eastern Europe (2nd ed.). Newton Abbott: David & Charles. ISBN 0-7153-4077-8.