Steam Locomotive Classes
Note: This FAQ section was not meant to be a comprehensive list of features or history of locomotive classes. Some classes have been selected for railfan interest, and in the case of locos that are restricted to certain areas, information on where they may be seen today has been provided. Detailed information on dimensions and operating figures, makers' lists, lines worked, etc., can be found in standard reference works on this topic such as the Hugh Hughes books (see the bibliography section).
Much background information on steam can be found on our web site at the Indian Steam Pages which include articles on the history of steam, newsletters of the Indian Steam Railway Society, and much more.
Some relevant sites on the web include the Diesel Loco Works' product web page, Chittaranjan Loco Works' web page and a page at IRIEEN on CLW's product range. You can see pictures of many classes of locomotives at the IRFCA Picture Gallery, and other sites such as RailInIndia.
Q. What are the technical specifications for the various loco classes?
The section on diesel and electric loco specifications has information on most diesel and electric locomotives of IR, and includes figures on power, max. speed, serial numbers, etc. The information is drawn mostly from Jal Daboo's book, with updates and additions from IRFCA members.
Also see the section on additional electric loco specifications which has comparisons of the passenger AC electrics, the freight AC electrics, and the WCAM series of AC-DC electrics.
For more complete information, see Jal Daboo's book or Hugh Hughes' books (see the book listing) or other such reference material on locos of IR. Loco specs can also be found at DLW's diesel locomotive products page and CLW's web page. There is some data on 3-phase locos such as WAP-5 and WAG-9 at IRIEEN's web site; and you can also find specs for WAG-7, WAP-4, etc. on that web site.
Both locomotives were fitted with Caprotti valve gear, and both had roller bearings on all engine and tender wheels; one Timken (3100) and one Skefco (3101). They weighed 99 tons, with an axle load of 18-2/3 tons, and a grate area of 45 sq ft.
The XP class was the basis for India's renowned WP class 4-6-2.The two locos carried GIPR running numbers 3100 and 3101, and on CR the all-India numbers were 22599 and 22600.
The ZD class as constructed was a modern 2-8-2 using a boiler based on the MG YL class (2-6-2) which had a pressure of 210lb. The 6 locos were built by Nippon Sharyo in 1957-58 to work trains on the two lines radiating north and south from Murtajapur. They had a 7 ton axle load.
- Tractive effort: 30,600lb
- Axle load: 18.5 tons
- Boiler: 5'11"
The WG may have the distinction of being the class of loco that was manufactured in the largest number of countries, as units were built in England, Scotland, Germany, Austria, USA, Japan, Switzerland, and of course in India.
Some WG locos were marked 'WGx'. This was not a separate class of loco, but simply indicated that the loco had CBC knuckle couplers for working block freight rakes, especially on SER.
However, the Indian WL 4-6-2 was a new class built in 1955. Initially, 10 locomotives were built by Vulcan Foundry. They were designed to operate passenger trains on lines denied to the WP class; and so are lighter and smaller. While the new standard express WP class weighed 102 tons, the WL weighed 89 tons, giving an axle load of 16¾ tons, against the WP's 18.5t. Five WLs were allocated to the Southern Railway, and five to the Northern Railway. Ten years later, production began at CLW, and WL 15014-15107 were built there in the years 1966-1968.
NR WL #15005 (VF, 1955) hauled the last regular BG steam service in November 1995, and this loco is now in the Rail Transport Museum.
They were large and powerful tank locomotives: they had the boiler and grate area of the WL class, with the WP's larger cylinders. Total weight of the WT was 123t, with an axle load of 18t. All of the post-war classes had a common boiler pressure of 210lb.
Much smaller were the six WT class 0-6-4T tanks built in 1925/6 for the Gaekwar's Baroda State railways. These locomotives had an axle load of 6t. In 1979, four WT were based at Nadiad, along with 1 W and 6 ZB and the other two were the sole power allocated to Devgadh Bariya.
Giesl ejectors, developed by the Austrian engineer Dr. Adolph Giesl-Gieslingen in the 1940s, consisted of a prefabricated nozzle and chimney with seven or more steam jets inline with the main nozzle and directed along it. The idea was to greatly improve the pumping efficiency of the exhaust within the loading gauge by using an oblong chimney (most of the length is below the boiler top line): depending on the original state of the loco, the Giesl ejector with superheater booster, produced notable fuel economies, and gains in available power.
IR ordered four Giesl ejectors in 1957: two were for WP locos, and two for AWE locos. The WP's were #3036 and #3037 (built by Wiener Lok, 1957); later WP's #7036 and #7037 were also fitted with Giesl ejectors. This was an unusual order -- in 1957, very few non-Austrian railways used Giesl ejectors. In 1964, 20 more ejectors were ordered, for WP/WG locos. In 1965 four more were ordered, two for WM locos and two for HPS locos. Finally, in 1966-67 85 were ordered for WG locos, and 45 for WP locos.
The first fully developed Giesl ejector went into operation on an Austrian express 4-8-0 in 1951, and over 2400 ejectors were built by 1966. They were widely used in the last years of steam: the East African Railways equipped most of their modern steam fleet with them.
In the days of steam, each steam boiler had an identifying number and its own schedule of maintenance. Boiler numbers were quoted in many ways, but a common format was something like '37/L/NG/1962'. In this, the 37 is the serial number, the L stands for a steam locomotive (although diesels and electrics don't have boilers, their equipment would use DL and EL instead), the NG refers to narrow gauge, and the 1962 refers to the year of manufacture.
The Bihta Accident The Locomotive Standards Committee set up in 1924 to update the BESA locomotive designs proposed several new designs for locomotives to be used in India. Among these designs known as the Indian Railway Standard or IRS classes was a 17 ton 4-6-2 locomotive design known as the 'XB' class.
These locos as well as the lighter 12.5 ton 4-6-2 'XA' class locos were involved in a number of minor derailments right from the beginning. On 17 July 1937, an XB loco hauling a mail train derailed at Bihta at an estimated speed of 96.5km/h, and over a hundred people died as a result. This tragedy received wide publicity. Although heavy monsoon rains had a role to play in undermining the track structure at the site of the derailment, it was determined that the tragedy was really caused by poor damping of lateral oscillations of the locomotive and its tender, which had over time also dangerously damaged the tracks. The investigation committee set up to look into the accident recommended that a deeper study be done into the design of the locomotive and ways to prevent such disasters.
As a result, in 1938, the Pacific Locomotive Committee was appointed and in its report published in 1939 recommended several significant changes to the loco design, such as modifications to the front bogie spring controls to damp the lateral oscillations, hind truck slides, and improved drawgear to couple the engine to its tender. Emphasis was also given to running these locos, even with the modifications, under strict speed limits.
However, World War II resulted in these plans for modified locomotives never materializing, and no purchase orders were placed with British manufacturers for any new XB locomotives. British manufacturers were fully occupied supplying required wartime locomotives. Instead, as the war progressed, India started receiving large numbers of locomotives from the USA and Canada (e.g., the X-Dominion or CWD 2-8-2, the AWD, AWE, etc.), which established a whole new set of loco designs in India, with their cast frames, integrated cylinders, and many other features including robustness in operation, and eventually this spelled the end of the old IRS set of loco designs in India.
For an alternative account of the accident, read Ken Staynor's article on the Bihta derailment.