In railway engineering, the term tractive effort describes the pulling or pushing capability of a locomotive. The published tractive force value for any vehicle may be theoretical—that is, calculated from known or implied mechanical properties—or obtained via testing under controlled conditions. The discussion herein covers the term's usage in mechanical applications in which the final stage of the power transmission system is one or more wheels in frictional contact with a railroad track.
Rail transport terms are a form of technical terminology applied to railways. Although many terms are uniform across different nations and companies, they are by no means universal, with differences often originating from parallel development of rail transport systems in different parts of the world, and in the national origins of the engineers and managers who built the inaugural rail infrastructure. An example is the term railroad, used in North America, and railway, generally used in English-speaking countries outside North America and by the International Union of Railways. In English-speaking countries outside the United Kingdom, a mixture of US and UK terms may exist.
Main components found on a typical steam locomotive include:
The British Railways Class D3/7 is a class of 0-6-0 diesel electric shunting locomotives built as LMS Nos. 7080–7119. The class were built from May 1939 through to July 1942 by the London, Midland and Scottish Railway at their Derby Works using a diesel electric transmission supplied by English Electric.
Under the Whyte notation for the classification of steam locomotives, 4-2-2 represents the wheel arrangement of four leading wheels on two axles, two powered driving wheels on one axle, and two trailing wheels on one axle.
The GWR 4100 Class was a class of steam locomotives in the Great Western Railway (GWR) of the United Kingdom.
The SZD Class AA20 was a one-off experimental 4-14-4 steam locomotive constructed by the Soviet Union by Krupp and the Voroshilovgrad Locomotive Factory in 1934 for the Sovetskie Zheleznye Dorogi (SŽD). Two locomotives were set to be built, but due to the construction of the railway's more powerful FD Class, only AA20-1 was built, leaving the second AA20 incomplete.
A coupling rod or side rod connects the driving wheels of a locomotive. Steam locomotives in particular usually have them, but some diesel and electric locomotives, especially older ones and shunter locomotives, also have them. The coupling rods transfer the power of drive to all wheels.
A steam turbine locomotive was a steam locomotive which transmitted steam power to the wheels via a steam turbine. Numerous attempts at this type of locomotive were made, mostly without success. In the 1930s this type of locomotive was seen as a way to both revitalize steam power and challenge the diesel locomotives then being introduced.
Engine balance refers to how the inertial forces produced by moving parts in an internal combustion engine or steam engine are neutralised with counterweights and balance shafts, to prevent unpleasant and potentially damaging vibration. The strongest inertial forces occur at crankshaft speed and balance is mandatory, while forces at twice crankshaft speed can become significant in some cases.
A jackshaft is an intermediate shaft used to transfer power from a powered shaft such as the output shaft of an engine or motor to driven shafts such as the drive axles of a locomotive. As applied to railroad locomotives in the 19th and 20th centuries, jackshafts were typically in line with the drive axles of locomotives and connected to them by side rods. In general, each drive axle on a locomotive is free to move about one inch (2.5 cm) vertically relative to the frame, with the locomotive weight carried on springs. This means that if the engine, motor or transmission is rigidly attached to the locomotive frame, it cannot be rigidly connected to the axle. This problem can be solved by mounting the jackshaft on unsprung bearings and using side-rods or chain drives.
In rail terminology, hammer blow or dynamic augment is a vertical force which alternately adds to and subtracts from the locomotive's weight on a wheel. It is transferred to the track by the driving wheels of many steam locomotives. It is an out-of-balance force on the wheel. It is the result of a compromise when a locomotive's wheels are unbalanced to off-set horizontal reciprocating masses, such as connecting rods and pistons, to improve the ride. The hammer blow may cause damage to the locomotive and track if the wheel/rail force is high enough.
A lateral motion device is a mechanism used in some railroad locomotives which permits the axles to move sideways relative to the frame. The device allows easier cornering.
The Be 4/6 12302 was one of four test locomotives ordered by the Schweizerische Bundesbahnen (SBB) in June 1917, along with the Be 3/5 12201, Be 4/6 12301 and Ce 6/8I14201. It was intended to be used on the Gotthardbahn, in order to gain experience in ordering and operating electric locomotives, However, the Be 4/6 12302 was never used for scheduled services on the Gotthard, because at its introduction it was already outperformed by the successor class Be 4/6 12303-12342.
Under the Whyte notation for the classification of steam locomotives, 4-2-2-0 represents the wheel arrangement of four leading wheels on two axles, four independently driven driving wheels on two axles, and no trailing wheels. The arrangement became known as double single.
A steam motor is a form of steam engine used for light locomotives and light self-propelled motor cars used on railways. The origins of steam motor cars for railways go back to at least the 1850s, if not earlier, as experimental economizations for railways or railroads with marginal budgets. These first examples, at least in North America, appear to have been fitted with light reciprocating engines, and either direct or geared drives, or geared-endless chain drives. Most incorporated a passenger carrying coach attached to the engine and its boiler. Boiler types varied in these earlier examples, with vertical boilers dominant in the first decade and then with very small diameter horizontal boilers. Other examples of steam motor cars incorporated an express-baggage or luggage type car body, with coupling apparatus provided to allow the steam motor car to draw a light passenger coach.
A Cartazzi axle is a design of leading or trailing wheel support used worldwide. The design was used extensively on the former LNER's Pacific steam locomotives and named after its inventor F.J. Cartazzi, formerly of the Great Northern Railway. It should not be confused with a pony truck as it does not pivot at all. The axle does, however, have sideways play built in to accommodate tight curves. Cartazzi's design causes the weight of the locomotive to exert a self-centring action on the trailing wheels.
The MÁV class 601 was a class of Hungarian four-cylinder Mallet locomotives, which was designed to haul long and very heavy cargo on very steep railway tracks. At 22.5 m long and outputting 2,200 kW (3,000 hp), they were the largest and most powerful steam locomotives built in Europe before and during World War I.
The Swiss locomotive class Ae 4/6 was a class of electric locomotives. They were intended as a powerful locomotive for the steep gradients of the Gotthard Railway, but smaller than the huge 'double locomotives' which had previously been tested there. They were built from 1941, during World War II, and although Switzerland remained neutral through this, material shortages led to some quality problems with these locomotives.
Rigid-framed electric locomotives were some of the first generations of electric locomotive design. When these began the traction motors of these early locomotives, particularly with AC motors, were too large and heavy to be mounted directly to the axles and so were carried on the frame. One of the initial simplest wheel arrangements for a mainline electric locomotive, from around 1900, was the 1′C1′ arrangement, in UIC classification.
