The Darjeeling Himalayan Railway's best-known and longest-lasting locomotive is the class B, which was built by several manufacturers from 1889 and is still in use today. Although the DHR had also procured larger locomotives and even Garratts, these small, two-axle saddle tank locomotives had apparently been best suited to the steep two-foot line with radii up to 60 feet. 

The coal capacity was later increased by planks. Due to the low quality of coal available and the cheap labor in India, the crew of these locomotives consists of up to six people. In addition to the driver, this includes two people who sit on the buffer beam and spread sand on the rails by hand. The fireman is assisted by one person who breaks the coal into equal-sized lumps and another who passes the coal to the fireman.

Locomotive Magazine, September 1918

The 34 class B members, supplied by British and American manufacturers, took on the brunt of the traffic over the decades. In 1997 they were reinforced by diesel locomotives as their number decreased due to age. Today most regular trains are pulled by the diesel locomotives, while class B mainly only takes on tourist trains. A locomotive came to the Beeches Light Railway in Great Britain around 2000, where it was used until the line closed in 2023.

Chief engineer Robert White had five ten-wheelers built for mail traffic on the meter-gauge lines of the South Indian, including those leading to Ceylon. These used the BESA standard design and came from Hawthorn, Leslie & Co. of Newcastle. Thus they had 16.5 inch diameter outside cylinders, 57 inch diameter coupled wheels and Belpaire firebox with a long narrow grate. 

However, only one engine was built according to the design using saturated steam, the others being the first narrow-gauge superheated locomotives in India. With the results of the five locomotives, White was able to substantiate his assumption that superheated steam should have a clear advantage despite the greater complexity. Thus, the only saturated engine was soon rebuilt with a superheater. 

The Nilgiri Mountain Railway in Southern India had 17 miles of adhesion track and 12 miles equipped with a rack rail of the Abt system. As they needed more powerful locomotives, they ordered the first six X class 0-8-2RT locomotives which were delivered by the Swiss SLM in 1914. Four followed in 1920 and two in 1925.

They had a rack drive of the Winterthur system, what promised savings in coal of up to 35 percent. This meant that the high and low pressure cylinders were on top of each other. The low pressure cylinders turned the two rack wheels via a 1 to 2,1 reduction gear. The position of these rack wheels can be seen in the long distance between the second and third driving axles. To allow for more flexibility in curves, the first and fourth driving axles were movable sideways.

Original appearance

flickr/Historical Railway Images

When the NMR saw the requirement for additional locomotives in 1952, SLM delivered an additional five. In 2002, the first X class locomotives were converted to run on diesel fuel, which can be distinguished by the additional saddle tank. To reduce wear and tear on the existing locomotives, the Golden Rock Railway Workshop built four new between 2011 and 2014. Two more were built in 2021 and 2022, of which one is coal fired.

The class YD was a metre-gauge goods locomotive developed in accordance with the Indian Railway Standard (IRS) rules. Its direct basis were ten Mikados built in 1927 by the Vulcan Foundry for the Assam Bengal Railway which were later designated YD/1. The boiler was closely related to that of the YC Pacific, but shorter.

Assam Bengal Railway No. 211, built by Vulcan Foundry

flickr/Historical Railway Images

Up to 1953, at least 270 were built by manufacturers from Britain, Germany, Czechoslovakia, India and Japan. The 25 locomotives produced in Japan had been built by Nippon Sharyo for Pakistan in 1952 and were oil-fired. Some had also come to Myanmar, of which a few were still in service after 2010. Generally, there are still many which were preserved.