Indian locomotive class HP

The Class HP (Heavy Passenger) was a broad gauge steam locomotive introduced in 1906 for heavy passenger trains on the railways in British India. It was one of the BESA locomotives developed by the British Engineering Standards Committee, later called the British Engineering Standards Association (BESA).

BESA class HP
HPS 24467 on display at the National Rail Museum, New Delhi.
Type and origin Power type Steam Designer British Engineering Standards Association Builder Vulcan Foundry North British Locomotive Co. Robert Stephenson & Co. Kitson & Co. William Beardmore & Co. Build date 1906-1950
Specifications Configuration: ​  • Whyte 4-6-0  • UIC 2′C n2 Gauge 1,676 mm (5 ft 6 in) Leading dia. 3 ft 7 in (1,092 mm) Driver dia. 74 in (1,880 mm) Wheelbase: ​  • Leading 7 ft 0 in (2,134 mm)  • Coupled 6 ft 9 in (2,057 mm)  • incl. tender Variant with 3000 gallon tender: 50 ft 7 1 ⁄ 2  in (15,430 mm) Length: ​  • Over buffers Variant with 3000 gallon tender: 60 ft 9 3 ⁄ 4  in (18,535 mm) Width 9 ft 6 in (2,896 mm) Height 13 ft 6 in (4,115 mm) Axle load 16.8 long tons (17.1 t) Service weight with 3000 gallon tender: 107 t with 4000 gallon tender: 113 t with 4500 gallon tender: 126 t Water cap. 3,000 or 4,000 or 4,500 imperial gallons (14,000 or 18,000 or 20,000 L; 3,600 or 4,800 or 5,400 US gal) Firebox: ​  • Type Belpaire  • Grate area 32 sq ft (3.0 m2) Boiler pressure 180 psi (12.4 bar; 12.7 kgf/cm2) Heating surface: ​  • Tubes 1,880 sq ft (175 m2)  • Total surface 2,037 sq ft (189.2 m2) Cylinders Two, outside Cylinder size 20 in × 26 in (508 mm × 660 mm) Valve gear Walschaerts Valve type Slide (HP class) Piston (HPS/HPC class)
Performance figures Tractive effort Starting: 11.2 bar boiler pressure: 101 kN (23,000 lbf) 9.3 bar boiler pressure: 84 kN (19,000 lbf)
Career Operators East Indian Railway Company North Western Railway Eastern Bengal Railway Great Indian Peninsula Railway Locale British Raj (until 1947) India (from 1947) Pakistan (from 1947) Bangladesh (from 1971) Retired 1980s-early 1990s Preserved 2 (India) 1 (Bangladesh) Disposition Three preserved, remainder scrapped

History

The HP class was the locomotive intended for heavy passenger traffic, which was first proposed in the BESA standard of 1907. Like the AP class, the HP was offered with three different large tenders, the small one holding 3000 gallons of water, the medium 4000 and the large 4500.

The HP class locomotives were delivered to various railways, but only the Indian States Railways (ISR) gave their locomotives the designation HP. They were built by several British locomotive factories, including the Vulcan Foundry, Robert Stephenson and Company, North British Locomotive Company, Kitson and Company and William Beardmore and Company.

Later, the HPS series was introduced, fitted with the Schmidt smoke tube superheater system - the S stands for superheated, and the HPC series for the locomotives with superheaters converted from the HP series, where the C stands for converted.

• 
  Variant with 3000 gallon tender
• 
  Variant with 4000 gallon tender
• 
  Variant with 4500 gallon tender

Preservation

Three HPS series locomotives have been preserved:

• HPS 30 of Bangladesh Railway in Rajshahi
• HPS 32 of Indian Railways at the Rail Museum, Howrah
• HPS 24467 of Indian Railways at the National Rail Museum of India, New Delhi.

Working	Class	Number	Location	Built	Zone	Builders	Build No	Name
No	HPS	30	Rajshahi Railway HQ
No	HPS	32	Regional Rail Museum Howrah		ER
No	HPS	24467	National Rail Museum	1950	RB	Vulcan Foundry Ltd, Newton Le Willows

• 
  Preserved superheated HPS variant of the Bangladesh Railway
• 
  Preserved superheated HPS variant in the National Rail Museum of India

Technical aspects

The locomotive was a two-cylinder saturated steam engine with a Belpaire firebox . The grate was arranged between the coupling gear sets, for which the wheel base between axles 2 and 3 was increased. The cylinders were arranged on the outside and the drive was on the second axle. The saturated HP class had Walschaerts valve gear with slide valves; piston valves were used in the superheated HPS and HPC classes. The running plate was set low, so splashers had to be fitted above the driving wheels. As with the AP class locomotives, the line of the driver's cab floor is raised in an arc to the height of the running plate. A small cow catcher was attached to the front buffer beam. The driver's cab was completely closed, with the rear wall of the driver's cab being formed by the three-axle tender. The three-axle tender was equipped with running boards and handrails along the side walls, which made it possible to reach the train from the locomotive while in motion.