Bengal Nagpur Beyer-Garratt Locomotives in India

Class HSG (Locobase 687)

Data from Wiener, Articulated Locomotives (1930) and "Bengal-Nagpur-Design 1166", Beyer-Garrrat Patent Articulated Locomotives (Manchester, England: Beyer-Peacock & Company Limited, 1931), archived on flickr's Historical Railway Images at [], et seq, p. . Other sources were [], first visited 14 November 2003. Sundar later relocated his website to [], last accessed 24 August 2021.

For Garratts (or any non-North American engine, for that matter) these are large engines and, like most Garratts, fitted with Belpaire fireboxes.

Doctor Sundar's website noted that they used many parts common to the Consolidation design that was part of the BESA series. Doctor Sundar credits the design with a 2,550-tonne (2,856-short ton) trailing load capacity on the level. B-P calculated a total tractive effort fot the 26 Garratts as 1,891,500 lb (857,971 kg/8,414 kN). Wiener claimed that they pulled 1,500-1,600-ton trains up sections of 1% grade between Chakardapur and Jharsaguda.

Although supplanted by electrification, they were retained in storage until as late as 1969.

Class N (Locobase 688)

Data verified and supplemented from Gavin Hamilton's excellent compilation of Garratt data posted at []

(6 September 2005); and "Bengal-Nagpur-Design 1152", Beyer-Garrrat Patent Articulated Locomotives (Manchester, England: Beyer-Peacock & Company Limited, 1931), archived on flickr's Historical Railway Images at [], p. 76-77. Other sources were [], first visited 14 November 2003. Sundar later relocated his website to [], last accessed 24 August 2021.

These were monster engines. At the time, they were the biggest to operate in India, the largest locomotives in the world running on 5' 6" gauge, and, said the 1931 B-P guide, the "largest locomotive yet built in Europe." Like most other Garratts, they were fitted with four simple-expansion cylinders with piston valves, superheaters, Walschaert's valve gear, and Belpaire fireboxes.

Sundar commented in 2003 that outfitting these with "more modern straight-ported cylinders with piston valves" was really necessary: "Whether such features gave better performance while hauling slow, heavy coal traffic is an open question."

The B-P guide mused on the significance of this design: "[T]he Garratt principle has, in this particular example, has been applied with advantage to a straight and comparatively well-laid track where light axle load and flexibility is not so important a factor as the development of high tractive effort on a normal axle load for handling heavy freight trains at speed."

They were designed for 1,600-ton coal trains from Anara and Tatanga in the heart of "immense areas" that the 1931 B-P guide described as "bearing some of the richest mineral deposits in the world". were later diverted to the ore-train service between Dalli Rajhara and Bhilai. Power for the grade meant a tonnage rating of 2,400 tons on 1% grade and a maximum speed of 45 mph (72.5 kph) on the level.

Coal consumption pulling the usual load of 1,650 tons on the Adra-Chakardharpore section was 10% lower than for the two 2-8-0 locomotives that had pulled the same train load while posting higher speeds.

The NMs were similar except for slightly smaller cylinders; see Locobase 689. When the Ns entered service, ten had piston valves; the other six equally divided between Caprotti and RC poppet valves. These latter engines later received piston valves.

BP's builder's numbers were 6583-6598; 6594 is a resident of India's National Railway Museum. S. Shankar's NRM website -- [] -- describes this class: "A behemoth hulking over pygmy locomotives is this mighty Garratt engine, undisputedly the heaviest and most powerful steam locomotive class ever used on the IR."

Class NM (Locobase 689)

Data verified and supplemented from Gavin Hamilton's excellent compilation of Garratt data posted at []

(6 September 2005); and "Bengal-Nagpur-Design 1166", Beyer-Garrrat Patent Articulated Locomotives (Manchester, England: Beyer-Peacock & Company Limited, 1931), archived on flickr's Historical Railway Images at [], et seq, p. 78. Other sources were [], first visited 14 November 2003. Sundar later relocated his website to [], last accessed 24 August 2021. Works numbers were 6705-6714 in 1931

These Twelve-wheeler Garratts pulled coal and ore trains and were identical to the slightly earlier Ns (Locobase (including the Belpaire firebox) except for their smaller size and lighter weight. In particular, the NMs had an axle loading that probably opened more of the broad gauge network than was available to the Ns.

The website [] noted that the firebox had thermic syphons and arch tubes. Tonnage rating was 3,000 tonnes (3,360 short tons) on level track.

Class P (Locobase 690)

Data from Gavin Hamilton's excellent compilation of Garratt data posted at []

(6 September 2005). See also Martyn Bane's archived copy of the report "New Beyer-Garratt Locomotives, Bengal-Nagpur Railway", reprinted from 5 January 1940 Railway Gazette (Manchester: Beyer, Peacock & Co, Ltd.). Last accessed 23 September 2011 at [] . Works numbers were 6931-6934.

Husky Double Mountain Garratts for the steep grades of Nepal. Delivered several years later than the N and NM class, the Ps had two more carrying axles that spread the weight and allowed traversing of even tighter curve radii and operation on 75-lb/yard (31-kg/metre) rail. Thus, although the P had a boiler slightly larger than that of the N class, making it the biggest in India, but an axle loading more comparable to the NMs.

Its tonnage rating, according to

The website [] (visited 14 November 2003), was 1,500 tonnes (1,680 short tons) up 1.1%.

The [] site (31 Dec 2003) adds that the P's Belpaire firebox's big grate required that the crew include 2 firemen and sometimes a third man to push the coal forward. The firebox was fitted with 2 thermic syphons as well as arch tubes. Steam admission to the cylinders came through 11" piston valves.

NB: Tube length is between sheets.