The Bengal Nagpur Railway class NM was a class of ten 4-8-0+0-8-4 Garratt locomotives manufactured by Beyer, Peacock & Company in England. This was modified N class Garratt. It had Thermic siphon and arch tubes for better performance. It worked on the Bilaspur-Katni line and Anuppur-Chirmiri branch line for hauling coal. Probably because of Poppet valves, they retired early.[1]
| Class NM |
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| Specifications |
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Configuration:
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| • Whyte | 4-8-0+0-8-4 |
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| Gauge | 5 ft 6 in (1,676 mm) |
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| Driver dia. | 4 ft 8 in (1.422 m) |
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| Axle load | 17.5 long tons (17.8 t) |
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| Adhesive weight | 138.55 long tons (140.77 t) |
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| Loco weight | 204.15 long tons (207.43 t) |
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| Fuel type | Coal |
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| Fuel capacity | 8 long tons (8.1 t) |
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| Water cap. | 6,000 imp gal (27,000 L; 7,200 US gal) |
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| Firebox: | |
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| • Grate area | 67.6 sq ft (6.28 m2) |
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| Boiler pressure | 210 psi (1.45 MPa) |
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| Heating surface | 2,961 sq ft (275.1 m2) |
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Superheater:
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| • Heating area | 642 sq ft (59.6 m2) |
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| Cylinders | Four, outside |
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| Cylinder size | 20 in × 26 in (508 mm × 660 mm) |
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| Valve gear | Lentz or Caprotti |
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| Valve type | Poppet |
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| Career |
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| Operators | |
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| Numbers | - BNR: 826–835
- →IR: 38826–38835
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| Locale | East Central Railway zone |
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| First run | 1931 |
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| Last run | 1960 |
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| Withdrawn | 1960 |
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| Preserved | 0 |
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| Scrapped | 1960 |
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| Disposition | Scrapped |
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| Technical specifications
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| Boiler diameter |
7 ft 1+13⁄16 in (2.18 m)
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| Heating surface of firebox |
330 sq ft (31 m2)
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| Maximum train load |
3,000 long tons (3,000 t) on level track
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