'X' Class locomotives (Nilgiri Mountain Railway)

Nilgiri Mountain Railway X class
Black locomotive with a blue cab
Nilgiri Mountain Railway locomotive No.37385, preserved at the Delhi Railway Museum
Type and origin
Power typeSteam
BuilderSwiss Locomotive & Machine Works, Winterthur, Switzerland (17)
Golden Rock Railway Workshop, Golden Rock, Tiruchirappalli, India (6)
Build date1914, 1920, 1925, 1952, 2011-2014, 2021-2022
Total produced23
RebuilderPonmalai Goldenrock (G.O.C.)
 • Whyte0-8-2RT
Gauge1,000 mm (3 ft 3+38 in) metre gauge
Driver dia.815 mm (32.09 in)
Fuel typeCoal or fuel oil
Fuel capacity2011: 850 litres (190 imp gal; 220 US gal) of diesel and 2,250 litres (490 imp gal; 590 US gal) of fuel oil
CylindersFour, outside, compound
High-pressure cylinderAdhesion: 450 mm × 410 mm (17.72 in × 16.14 in)
Low-pressure cylinderRack: 450 mm × 430 mm (17.72 in × 16.93 in)
Valve gearWalschaerts
Performance figures
Maximum speedAdhesion: 30 km/h (19 mph)
Rack: 15 km/h (9 mph)

The X class is a metre gauge 0-8-2RT rack and pinion compound locomotive used by the Nilgiri Mountain Railway in the Nilgiri Hills of southern India. They are used on the 28-kilometre-long (17 mi) section between Coonoor and Mettupalayam, where the steepest gradient is 1 in 12.5. The railway uses the Abt system on these steep sections. The locomotives have two high-pressure and two low-pressure cylinders, located outside the locomotive's frames. The low-pressure cylinders drive the rack gears, and are positioned above the two main high-pressure cylinders which drive the main wheels.

This class of engine was acquired to replace the line's original Beyer, Peacock & Company 2-4-0RT rack locomotives, which were not powerful enough to handle the traffic.[1][2] The X-class locomotives were bought in two batches from the Swiss Locomotive & Machine Works, Winterthur, Switzerland. The first batch of 12 was delivered between 1914 and 1925, and the second batch of five was delivered in 1952.[1][3] Four more members of the class were built in India between 2011 and 2014. Two more were Again built in India between 2021 and 2022

Class Table[]

Table of orders and numbers[4][5]
SLM Works Nos. Year Quantity NMR No. All India No. Notes
Swiss Locomotive Works, Winterthur (SLM) orders
2456–2459, 2469–2470 1914 6 1–6 37379–37384 ex-No. 1-6, 37379-37383 (1-5) scrapped off during the British Raj
2734–2736, 2733 1920 4 7–10 37385–37388
3000–3001 1925 2 11–12 37389–37390
4069–4073 1952 5 13–17 37391–37395
Golden Rock, Ponmalai (GOC) orders
n/a 2011 - 2014 4 18–21 37396–37399 Non-SLM, All Oil-powered, Now all made to run on High speed diesel instead of Furnace Oil
n/a 2021 - 2022 2 22–23 37400–37401 37400 (Coal Powered) and 37401 (High speed diesel powered), rolled out in August 2021 and September 2022 respectively.

Conversion to oil[]

Black-and-blue locomotive, converted from coal to oil firing
Locomotive No.37395 at Coonoor Shed, February 2005

The coal-fired Locomotive No. 37395 was modified to oil firing in 2002, and another locomotive was similarly modified shortly afterwards. The railway intends to convert more locomotives to oil-fired system, since they are less likely to spark forest fires and are easier to refuel. Unlike coal-fired engines which require two firemen, only one fireman needs to travel with the driver of an oil-fired locomotive.[6][7] Now all Oil-Fired steam engines run on High Speed Diesel, owing to Lesser Sulphur content and Lesser Viscosity compared to Furnace Oil

New locomotives[]

To ease the load on existing X-class locomotives, four oil-fired X-Class 0-8-2RT rack and pinion compound engine steam locomotives with a similar design were ordered. The first one (No. X 37396), named "Neela Kurinji" arrived in February 2011 and entered service on March 24 of that year. The second one (X 37397), named "Betta Queen" was rolled out at the Golden Rock Railway Workshop in February 2012, and entered service on the railway in March. The third one built by Golden Rock, Trichy (X 37398), named "Nilgiri Queen", entered service in March 2013. The fourth (X 37399), named "Nilgiri Flycatcher" was rolled out on March 5, 2014 at the Central Workshop in Ponmalai, Tiruchirapalli, to join the fleet after trials on the railway.

In 2020, under Central Govt's order, Ponmalai Goldenrock (G.O.C.) started manufacture of one coal-powered and one oil-powered X-Class Steam Engine, But due to COVID-19, lockdown etc, could not finish and roll out on time (Source:- Deccan Herald). X-37400 (NMR no. 22), the Coal-powered locomotive, was rolled finally out on August 25, 2021 and is now in Service. Oil (aka High Speed Diesel) Fired locomotive X-37401 (NMR no. 23) rolled out recently, on September 26 2022 and also has joined service

In fiction[]

Ashima, a character based on the X Class and voiced by Tina Desai, appears in the 2016 animated film Thomas & Friends: The Great Race. She also appears in the twenty-second series, the twenty-third series and the twenty-fourth series of Thomas & Friends. [8][9][10]

In Bollywood[]

The X-class Steam Engines were temporarily repainted and used in the song Chayya Chayya, sung by Sukhwinder Singh and Sapna Awasthi, with music composed by A R Rahman and lyrics by Gulzar. This song features Shah Rukh Khan and Malaika Arora dancing on the Train, from the 1998 Mani Ratnam movie Dil Se. For shooting the song, Mani Ratnam spoke to NMR for painting the X-class Steam Engines in Greenish Black Color and the Train Rakes in Brick Color, for 5 days, as the shooting took 108 hours (4.5 days).



  1. ^ a b Bhandari, R. R. (2008). "Steam in history". IRFCA. Retrieved 2 March 2010.
  2. ^ "Blue Mountain Railway". India for Visitors. indiaforvisitors.com. 2003. Retrieved 2 March 2010.
  3. ^ "National Railway Museum". Rail in India. Retrieved 2 March 2010.
  4. ^ Hughes 1992, p. 98
  5. ^ Hughes 1996, p. 58
  6. ^ Rajaram, R. (21 December 2009). "Work for manufacturing four new oil-fired steam locos begins". The Hindu. Chennai, India. Archived from the original on 31 December 2009.
  7. ^ "Oil fired Steam engine on Nilagiri Railway , India". Encyclopedia.com. HighBeam. 2009. Retrieved 2 March 2010.
  8. ^ "Meet Ashima, and Her Impact on Child Product Sales to India". India Briefing. March 31, 2016. Archived from the original on December 7, 2016. Retrieved July 13, 2017.
  9. ^ "Ashima - Character Profile & Bio". Thomas & Friends - Official Website. Retrieved August 26, 2017.
  10. ^ "Flying Scotsman on track to star in new 'more diverse' Thomas the Tank Engine film". ITV News. April 6, 2016. Archived from the original on August 11, 2016. Retrieved July 13, 2017.


  • Hughes, Hugh (1992). Indian Locomotives, Part 2 – Metre Gauge 1872–1940. Harrow, Middlesex: Continental Railway Circle. ISBN 978-0-9503469-9-1.
  • Hughes, Hugh (1996). Indian Locomotives, Part 4 – 1941–1990. Harrow, Middlesex: Continental Railway Circle. ISBN 978-0-9521655-1-4.

External links[]

Media related to Nilgiri Mountain Railway class X at Wikimedia Commons