BNR class N

The Bengal Nagpur Railway class N was a class of 4-8-0+0-8-4 Garratt steam locomotives built by Beyer, Peacock & Company in England in 1929. At the time of their construction, they had the largest water capacity of any Garratt, in addition to being the largest locomotives in India. The class N Garratts were introduced following successful performance results from the earlier HSG Garratts. Due to their heavy weight, they were restricted to 90 lb/yd (45 kg/m) rails. They had straight-ported cylinders; it is not known if this was suitable for slow, heavy coal traffic. Like the earlier HSG Garratts, they worked on the Chakradharpur-Jharsuguda and the Anara-Tatanagar sections. After electrification, they were used at Rourkela. They could haul 2,400 t (2,362 long tons; 2,646 short tons) on a 1 in 100 gradient.^[1]

BNR class N
Preserved class member 815 (BP 6594/1930) at the National Rail Museum, New Delhi
Type and origin Power type Steam Builder Beyer, Peacock & Company Serial number 6583–6598 Build date 1929 Total produced 16
Specifications Configuration: ​  • Whyte 4-8-0+0-8-4  • UIC (2′D)(D2′) h4t Gauge 5 ft 6 in (1,676 mm) Driver dia. 4 ft 8 in (1.422 m) Axle load 20.25 long tons (20.57 t; 22.68 short tons) Adhesive weight 159.4 long tons (162.0 t; 178.5 short tons) Loco weight 234 long tons (237.8 t; 262.1 short tons) Fuel type Coal Fuel capacity 14 long tons (14.2 t; 15.7 short tons) Water cap. 10,000 imp gal (45,000 L; 12,000 US gal) Firebox: ​  • Grate area 69.8 sq ft (6.48 m2) Boiler pressure 210 psi (1.45 MPa) Superheater: ​  • Heating area 642 sq ft (59.6 m2) Cylinders Four, outside Cylinder size 20+1⁄2 in × 26 in (521 mm × 660 mm) Valve gear Walschaerts Valve type Piston valves
Performance figures Maximum speed 45 mph (72 km/h) Tractive effort 69,655 lbf (309.84 kN)
Career Operators Bengal Nagpur Railway →Indian Railways Numbers BNR: 810–825 →IR: 38810–38825 Locale South Eastern Railway zone First run 1929 Last run 1970 Retired 1970 Withdrawn 1970 Preserved No. 811 and 815 Current owner National Rail Museum, New Delhi and Kharagpur Workshops

In 2006, class member 811 at Kharagpur workshop was returned to working order and used on a few runs^[2] before being stored again. Many parts were borrowed from class member 815 at the National Rail Museum of India in order to achieve this. The parts were later returned and refitted to 815, which was given a cosmetic overhaul. In 2018 a second attempt to return 811 to working order was made; this time all missing parts were fabricated in a US$400,000 refurbishment that was put out to public tender. The locomotive had one test run in late 2019, and has remained on static display as of 2024.^[2]

History

The locomotives were imported by the BNR, following the success of the HSG class garratt locomotives. They were built by Beyer, Peacock and Company Limited between 1929 and 1930. 16 units of these locos were built and supplied. On the BNR and later Indian Railways, they were classified as class N. Due their high hauling capacity and tractive effort, they were used to haul heavy freight trains weing up to 3000-4000 metric tons. After the restructuring of the railways in the 1950s, the locomotives were transferred to the Southern eastern railway zone. Their serial numbers gaot the prefix 38***. They are the heaviest locomotives which operated in India with a weight of 234 metric tons. With their increasing age and with dieselification and electrification of the railway, they were relegated to haul smaller passenger and freight trains. By 1970, most of them had been withdrawn from service and used for shunting and the units were slowly scrapped. Two examples numbered 811 and 815 are preserved. 815 is housed at the National Railway Museum of New Delhi. 811 is housed at the Kharagpur workshop and has been restored to working order.

Technical specifications

Boiler diameter	7 ft 1+13⁄16 in (2.18 m)
Boiler area	3,112 sq ft (289.1 m2)
Max train load	3,000 long tons (3,048.1 t; 3,360.0 short tons)

The locomotives were built by. Beyer, Peacock and Company Limited in 1929. A total of 16 were built. They were the heaviest steam locomotives operating in India ever. The locomotives had to tenders, one leading, which carried water and the rear one carried water and coal for the locomotive. The water from these tenders was pumped to the central boiler and operated on steam. If the water level in the leading tender went down, the tractive effort of the engine decreased. It was rated at around 309 kilonewtons. The two tenders were connected to the central boiler via pivot joints which helped the locomotives negotiate curves. The locomotives were powered by two bogies powered by two piston cylinders each, one on each side of the bogie. The locomotives could operate in both directions. They were used to haul heavy freight loads up to 4000 metric tons on the Bengal Nagpur section and later on the Southern eastern railway zone until they being withdrawn from service. The top speed of the locomotives was around 72 kmph. The locomotives were equipped with vacuum brakes for the locomotive as well as the train. They were withdrawn in 1970s. Two units out of the 16 built, survive. One at the National Railway Museum at New Delhi and one at Kharagpur workshop, the latter being in working order. It was of the Garrett type design. The wheel arrangement was 4-8-2+2-8-4.

See also

• Indian Railways
• Rail transport in India § History
• Locomotives of India
• Rail transport in India