Switcher locomotive
 | This articleneeds additional citations forverification.(January 2023) |
Aswitcher locomotive(American English),shunter locomotive(British English), orshifter locomotive(Pennsylvania Railroadterminology) is alocomotiveused for maneuvering railway vehicles over short distances. Switchers do not usually movetrainsover long distances, instead they typically assemble trains in order for another locomotive to take over. Switchers often operate in arailyardor make short transfer runs. They may serve as the primary motive power on shortbranch linesorswitching and terminal railroads.[1][2][3]
Switchers are optimized for their role, being relatively low-powered but with a high startingtractive effortfor getting heavy cars rolling quickly. Switchers are geared to produce hightorquebut are restricted to low top speeds and have small diameterdriving wheels.Switchers tend to be durable and to remain in service for a long time,[4]such as theSwedish class U.
American, Russian, Indian and Chinese switchers tend to be larger, withbogiesto allow them to be used on tight radiuses. Western European shunters tend to be smaller and more often have fixed axles[citation needed].They also often maintainedcoupling rodsfor longer than other locomotive types, although bogie types have long been used where very heavy loads are involved, such as at steelworks.
Etymology[edit]
A switcher may also be called a yard pilot, switch engine, or yard goat.
The term can also be used to describe the workers operating these engines or engaged in directing shunting operations. Switching locomotives may be purpose-built engines, but may also be downgraded main-line engines, or simply main-line engines assigned to switching. Switchers can also be used on short excursion train rides.
Power types[edit]
Diesel[edit]
Dieselswitchers tend to have a high cab and often lower and/or narrowerhoods(bonnets) containing the diesel engines, for all round visibility.Slugsare often used because they allow even greater tractive effort to be applied. Nearly all slugs used for switching are of the low hood, cabless variety. Good visibility in both directions is critical, because a switcher may be running in either direction; turning the locomotive is time-consuming. Some earlier diesel switchers usedcow-calfconfigurations of two powered units in order to provide greater power.
Modern diesel switchers are usuallydiesel-electric locomotives.
Electric[edit]
The majority of modern switchers are diesels, but countries with near-totalelectrification,like Switzerland, useelectricswitchers. Prior to the introduction of diesel-electric locomotives, electric shunting locomotives were used to an extent in Great Britain where heavy trains needed to be started on steep gradients. The steeply-graded Quayside Branch inNewcastle upon Tynewas electrified by theNorth Eastern Railwayin 1905, and two steeplecab locomotives were built to handle all traffic on the line. One of these,No. 1,is now part of the National Collection and resides atLocomotioninShildon.On the opposite side of the Tyne, the electrified lines owned by the Harton Coal Company inSouth Shieldsfor the movement of coal and colliery waste to shipping facilities on the river was one of the more extensive industrial networks. A number of the earlyGermanlocomotives built for use on these lines have been preserved.
Electric locomotives were also extensively employed for moving the coke cars atcokeworks,obtaining power from a side wire, asthird railoroverhead lineelectrification would have been impractical. These specialised locomotives were tall steeple-cab types not seen anywhere else, and operated on a short length of track between the ovens and the quenching tower. Despite their ubiquity, very few have survived into preservation as there is very little scope of operating them due to their unique means of obtaining power, slow speed and the fact they greatly exceed the loading gauge of most railway lines. One example built byGreenwood and BatleyinArmley,Leedsis preserved at theMiddleton Railway,not far from where it was built.
Small industrial shunters are sometimes battery powered type. An early battery-powered shunting locomotive is shown here.[5]TheTyne and Wear Metrohas three battery electric shunters built byHunslet,which are used to haul engineering trains when the overhead supply is switched off.New Zealand Railwaysimported and manufactured locally battery-electric shunters in the 1920s: theEB classand theE class (1922)
Electro-diesel[edit]
Some switchers areelectro-diesel,and hence can be powered from onboard diesel engines, or from an external electricity supply.
Steam[edit]
Steam shunter/switchers are now mostly out of service.Steamswitchers were eithertank locomotivesor had special (smaller)tenders,with narrowcoal bunkersand/or sloped tender decks to increase rearward visibility. Headlights, where carried, were mounted on both ends. Most were either side-tank or saddle-tank types, however in the usual departure from its neighbours' practice, theGreat Western Railwayusedpanniertanks for shunting and branch line work, a practice which the Western Region of BR perpetuated until steam traction was phased out, with several examples joining a9Fas banking engines to assist locomotives on the notoriously arduous ascent of the Lickey Incline, replacing theLMS "Jinties"which had formerly carried out the task alongside"Big Bertha".
As diesel shunters began to appear in ever-increasing numbers, attempts were made by companies such as Sentinel to adapt the vertical boilers from their steam powered road vehicles for use in shunting locomotives, in order to compete with the newcomers. Although these were found to be equal in power and efficiency to most of the early diesel designs, their development came too late to have any real impact. Outwardly, they bear more resemblance to diesels than steam locomotives. A number have been preserved onheritage railways,although few of these are in working order, being designed very specifically for shunting work and lacking the necessary speed to travel any kind of distance.
Small industrial shunters have sometimes beenfireless locomotivesand a few of these are still at work in Germany. Again, several have been preserved, but are mostly static displays, as heritage railways and museums lack the large source of high-pressure steam (such as apower station's boilers) needed to charge the locomotive's accumulator.
By region[edit]
United States[edit]
Americanswitchers tend to be larger, and are almost always powered by diesel.
Most American switchers are actuallyroad switchers,which are larger and have greater power output, to be used on mainlines.
Great Britain[edit]
British shunters are much smaller than those used in the United States. Current British shunters are0-6-0diesel-electrics,Class 08andClass 09,of 350-400 horsepower. These were developed from similar locomotives supplied by theEnglish ElectricCompany to theBig Four British railway companiesin the 1930s and 1940s, e.g. those pioneered by theLMS.Similar locomotives were exported to theNetherlands(e.g.NS Class 600) and Australia (e.g.Victorian Railways F class (diesel)). The use of shunting locomotives saw a sharp decline in Britain in the latter half of the 20th century, largely due to the contraction of the network, increased competition from road traffic and widespread adoption of train-load freight, with fixed rakes of wagons moving mainly bulk products between rapid-loading facilities, as opposed to thousands of sidings and goods depots feeding trains of assorted wagons into the marshalling yards.
Continental Europe[edit]
In continental Europe0-6-0(or "C" ) diesel-hydraulics, similar to the short-livedBritish Rail Class 14,are widely used. A very common type is theDB Class V 60and its variants. For lightweight shunting of single wagons or short trains, two-axle shunters are common; in Germany these are known asKleinlokomotive(small locomotive).
See also[edit]
References[edit]
- ^Burns, Adam (29 December 2022)."Switcher Locomotives: An Overview".US.Retrieved2 February2023.
- ^"New California Locomotives Designed to Reduce Emissions".UP.Retrieved13 February2023.
- ^"Cummins Develops Option to Help Switcher Locomotives Reduce Emissions".Finance.yahoo.com. 2 December 2021.Retrieved13 February2023.
- ^Solomon, Brian (2014).GE and EMD Locomotives.Voyageur Press. p. 56.ISBN9781627883979.
- ^"Electric locomotive, 1917".Ingenious.UK. Archived fromthe originalon 28 March 2016.Retrieved14 May2016.