{{Short description|Steam locomotive fuel and water tank container}} {{redirect|Coal car|the modified automobile once popular in Vietnam|Xe than|freight cars that carry coal|Hopper car|and|Gondola (rail)|and|Open wagon}} {{More footnotes needed|date=April 2009}} {{stack| [[Image:Sierra Railway 3 Tender.jpg|thumb|250px|[[Sierra Railway No. 3]] tender]] [[Image:65 SECR O1 class 2.jpg|thumb|250px|A British [[SER O class|SE&CR O1 class]] runs tender-first at the [[Bluebell Railway]]]] [[Image:Tender-Dampflok.JPG|thumb|250px|[[Cutaway drawing|Cutaway]] cross section showing a Spanish tender designed for fuel oil. Green areas hold water and brown areas hold fuel oil. There is a special arrangement to prevent sloshing around during the movement of the train.]] }}
A '''tender''' is a special [[railroad car|rail vehicle]] hauled by a [[steam locomotive]] containing its [[fuel]] ([[wood fuel|wood]], [[coal]], [[fuel oil|oil]] or [[torrefaction|torrefied]] [[biomass]]) and water. Steam locomotives consume large quantities of water compared to the quantity of fuel, so their tenders are necessary to keep them running over long distances. A locomotive that pulls a tender is called either a '''tender locomotive''' or a '''tender engine'''. Locomotives that do not have tenders and carry all their fuel and water on board are called ''[[tank locomotive]]s''.
A '''[[Gangway connection#Locomotives (corridor tenders)|corridor tender]]''' is a locomotive tender with a passageway to one side, allowing crew changes on the fly.
A '''brake tender''' is a tender that is heavy and used (primarily) to provide greater braking efficiency.
==General functions== The largest steam locomotives are semi-permanently coupled by a [[Drawbar (haulage)|drawbar]] to a tender that carries the water and fuel. The fuel source used depends on what is economically available locally. In the [[UK]] and parts of [[Europe]], a plentiful supply of [[coal]] made this the obvious choice from the earliest days of the steam engine. Until around 1850 in the [[Rail transport in the United States|United States]], the vast majority of locomotives burned wood until most of the eastern forests were cleared. Subsequently, coal burning became more widespread, and wood burners were restricted to rural and logging districts.
===Water supply=== [[File:SNCF 241P Class with 34P tender.jpg|thumb|[[SNCF 241P Class]] with 34P bogie tender, being filled from a water crane (Nantes Blotterau, France, August 1969)]]
[[Image:DixianaRightSide.JPG|thumb|right|250px|[[Shay locomotive]] ''[[dixiana (steam locomotive)|Dixiana]]'' at the [[Roaring Camp and Big Trees Narrow Gauge Railroad]], [[Felton, California]], with wooden [[water tower]] and extendable [[spigot]] visible in the background]]
<blockquote> By the mid-1800s, most steam locomotive tenders consisted of a fuel bunker (that held coal or wood) surrounded by a U-shaped (when viewed from the top) water jacket. The overall shape of the tender was usually rectangular. The bunker which held the coal was sloped downwards toward the locomotive providing easier access to the coal. The ratio of water to fuel capacities of tenders was normally based on two water-stops to each fuel stop because water was more readily available than fuel. One pound [{{cvt|1|lb|kg|disp=out}}] of coal could turn six pounds of water (0.7 gallons) [{{cvt|6|lb|kg|disp=out}}] to steam. Therefore, tender capacity ratios were normally close to 7 tons (14,000 lb) [{{cvt|14,000|lb|kg|disp=out}}] of coal per 10,000 gallons [{{cvt|10,000|usgal|L|disp=out}}] of water.<ref name='tenders08'>{{cite web|url=http://www.steamlocomotive.com/types/tenders/ |title=Steam Locomotive Tenders |access-date=2008-08-20 |work=Steamlocomotive.com }}</ref> </blockquote>
The water supply in a tender was replenished at water stops and locomotive depots from a dedicated [[water tower]] connected to [[water crane]]s or gantries. Refilling the tender is the job of the [[fireman (steam engine)|fireman]], who is responsible for maintaining the locomotive's fire, steam pressure, and supply of fuel and water.
Water carried in the tender must be forced into the [[boiler]], to replace that which is consumed during operation. Early engines used pumps driven by the motion of the pistons. Later, [[steam injector]]s replaced the pump while some engines used [[turbopump]]s.
====With track pans or water troughs==== In the UK, the USA and France, [[water trough]]s (in the USA, track pans) were provided on some main lines to allow locomotives to replenish their water supply while moving. A "water scoop" was fitted under the tender or the rear water tank in the case of a large tank engine; the fireman remotely lowered the scoop into the trough, the speed of the engine forced the water up into the tank, and the scoop was raised once it was full.
The fuel and water capacities of a tender are usually proportional to the rate at which they are consumed, although there were exceptions. The [[Pennsylvania Railroad]] and the [[New York Central Railroad]] used [[track pan]]s on many of their routes, allowing locomotives to pick up water at speed. The result was that the water tanks on these tenders were proportionally much smaller.
In the [[UK]] water troughs were used by three of the [[Big Four British railway companies|Big Four]] railways. The exception was the [[Southern Railway (Great Britain)|Southern Railway]] – mainly because the majority of the Southern's operations were based around short-distance commuter, suburban and rural services with frequent station stops where water could be taken on from [[water crane|water columns]]. The Southern's decision to [[electrification|electrify]] its routes into [[London]] with a [[third rail]] system also made the installation of water troughs impractical. Only on the former [[London and South Western Railway]] routes west of [[Salisbury]], where long-distance express trains operated, was the lack of troughs a problem. Rather than install troughs the L&SWR (and the Southern Railway) equipped its express locomotives with special high-capacity tenders with a water capacity of 4,000 gallons (18,200 L) running on a pair of twin-axle [[bogie]]s. These were known to railwaymen as "water cart" tenders.
===Condensing tenders=== [[File:SAR Class 25 3511 (4-8-4) Tender.JPG|thumb|left|Type CZ condensing tender from [[South African Class 25 4-8-4|South African Railways Class 25]] condensing steam locomotive no. 3480, with its large radiator section predominating]] [[Condensing steam locomotive]]s were designed to recycle exhaust steam by condensing it into feed water. The principal benefit is conservation of water, but the [[thermal efficiency]] of the engine is also increased, since much of the heat otherwise lost in the exhaust is used to preheat water injected into the boiler.<ref name="Ransome-Wallis.1">{{Ransome-Wallis Encyclopedia|pages=314–315}}</ref> In some cases condensing was employed simply to improve visibility by eliminating clouds of exhaust.<ref name="Ransome-Wallis.1"/>
A primitive approach to condensation simply injected the spent steam into the tender tank, relying on the mass of water for cooling.<ref name="Ransome-Wallis.1"/> More sophisticated tenders, such as those used in the [[South African Railways]] [[South African Class 25 4-8-4|Class 25]] locomotives designed for service in the [[Karoo]], replaced most of the water tank with a huge radiator, in which the steam was cooled and condensed. Exhaust steam, after passing through an [[oil-water separator]], was conveyed to the tender, where it powered a low-pressure turbine used to drive the radiator fans. The steam then passed into the radiator. The condensate was injected into the boiler with another turbine-driven pump.<ref name="Ransome-Wallis.2">{{Harvnb|Ransome-Wallis|2001|p=472}}</ref> This was a quite complex bit of machinery, also requiring another turbine in the smokebox to provide the exhaust draft normally obtained by blowing the exhaust steam up the stack.<ref name="Ransome-Wallis.2"/> Eventually the SAR examples were converted to conventional locomotives by replacing the radiator with a long water tank.<ref name="Durrant">{{Durrant-Twilight|pages=107-109}}</ref>
===Fuel supply=== A factor that limits locomotive performance is the rate at which fuel is fed into the fire. Much of the fireman's time is spent throwing wood or shoveling coal into the firebox of the locomotive to maintain constant steam pressure. In the early 20th century some locomotives became so large that the fireman could not shovel coal fast enough.<ref name="AMBell" >{{cite book |last=Bell |first=A Morton |year=1950 |title=Locomotives |edition=seventh |publisher=Virtue & Co Ltd |location=London }}</ref> Consequently, in the United States, various steam-powered [[mechanical stoker]]s (typically using an auger feed between the fuel bunker and the firebox) became standard equipment and were adopted elsewhere, including Australia and South Africa.
==Tender design variants== [[File:SEt-Lyon Loco Verpilleux.jpg|thumb|A locomotive and tender designed by [[Claude Verpilleux]] around 1842 for the [[Saint-Étienne]] to [[Lyon]] railway in France]] In the early days of railroading, tenders were rectangular boxes, with a bunker for coal or wood surrounded by a U-shaped water jacket. This form was retained up to the end of steam on many coal-burning engines. Oil-burning engines substituted a fuel tank for the bunker. Variations on this plan were made for operational reasons, in attempts to economize on structure.
=== Vanderbilt === [[File:4-8-4 Confederation type locomotive, 6100, Canadian National RR (CJ Allen, Steel Highway, 1928).jpg|thumb|Cylindrical Vanderbilt tender, of the Canadian National]] In early 1901, [[Cornelius Vanderbilt III]] filed a patent application covering a new type of tender.<ref>Cornelius Vanderbilt, Tender for Locomotives, &c., {{US patent|681760}}, granted Sept. 3, 1901.</ref> Vanderbilt was the great-grandson of the founder of the [[New York Central Railroad]]; his tender featured a cylindrical body like a [[tank car]] with a fuel bunker set into the front end. This design was soon adopted by a number of [[Rail transport in the United States|American railroads]] with oil-burning and coal-burning locomotives.<ref name="tenders08"/><ref>See Vanderbilt, Cornelius, "Locomotive Boilers" (1901), Baldwin Record of Recent Construction No. 23. This speech, delivered on January 8, 1901, to the junior members of the American Society of Mechanical Engineers, provides a detailed description of the design and construction of the boiler, as well as the results of numerous tests that Baldwin Locomotive Works had run.</ref>
Compared to rectangular tenders, cylindrical Vanderbilt tenders were stronger, lighter, and held more fuel in relation to surface area. Railroads who were noted for using Vanderbilt tenders include:<ref name="tenders08"/> *[[Baltimore & Ohio]] *[[Canadian National]] *[[Grand Trunk Western]] *[[Great Northern Railway (U.S.)|Great Northern Railway]] *[[Southern Pacific Transportation Company|Southern Pacific]] *[[Union Pacific]] *[[Hungarian State Railways]] (MÁV Class 203)<ref>{{cite web |url=https://www.steamlocomotive.com/locobase.php?country=Hungary&wheel=4-4-2&railroad=mav#1544 |title=Magyar Allamvasutak 4-4-2 Locomotives in Hungary |last=Barris |first=Wes |date= |website=steamlocomotive.com |access-date=2024-10-20 |quote=}}</ref> *[[New Zealand Railways Department]] ([[NZR AB class]], [[NZR J class (1939)|NZR J class]], [[NZR G class (1928)]]). *[[Nashville, Chattanooga and St. Louis Railway]] *[[Seaboard Air Line Railroad]] *[[South African Railways]]
===Whaleback=== [[File:Georgetown Loop No. 12 Tender.jpg|thumb|left|Whaleback tender built for the [[Kahului Railroad]] in 1928]] A form peculiar to oil-burning engines was the "whaleback" tender (also sometimes called a "turtle-back" or "loaf" tender). This was a roughly half-cylindrical form with the rounded side up; the forward portion of the tank held the oil, while the remainder held the water. This form was particularly associated with the [[Southern Pacific Transportation Company|Southern Pacific]].<ref name='tenders08'/>
===Slopeback=== [[File:Sunset Limited on the train-ferry at Port Costa, San Francisco (CJ Allen, Steel Highway, 1928).jpg|thumb|Locomotive with slopeback tender, loading the ''Sunset Limited'' onto the train-ferry ''Solano'' at [[:en:Port Costa, California|Port Costa]], San Francisco, [[Southern Pacific Railroad|Southern Pacific R.R.]] ]] In the United States, tenders with sloped backs were often used for locomotives in yard [[shunting (rail)|switching]] service, because they greatly improved the engineer's ability to see behind the locomotive when switching cars. The reduced water capacity was not a problem, as the tender's water tank could be frequently refilled in the [[rail yard]].<ref name="tenders08" /> In the 1880s, numerous locomotive manufacturers were offering tenders with this design on small [[switcher locomotive]]s.<ref>[https://books.google.com/books?id=TreSf6lRDygC&pg=PA120 Baldwin Locomotive Works Illustrated Catalogue of Locomotives, 2nd Ed.], Lipincott, Philadelphia, 1881; pages 120 and 146 provide a photographs.</ref><ref>[https://books.google.com/books?id=wERJAAAAYAAJ&pg=PA54 Illustrated Catalogue of Locomotives manufactured by The Dickson Manufacturing Company], Scranton, 1886; pages 32 and 123 provide the reason for the sloped back, pages 54 and 142 provide illustrations.</ref>
===Corridor=== {{Main|Corridor tender}} [[File:LNER pacific 4472 Flying Scotsman, with corridor tender (CJ Allen, Steel Highway, 1928).jpg|thumb|LNER Class A1 [[LNER Class A3 4472 Flying Scotsman|No. 4472 ''Flying Scotsman'']] with corridor tender]] For the introduction of the [[London and North Eastern Railway]]'s non-stop [[Flying Scotsman (train)|''Flying Scotsman'']] service on 1 May 1928, ten special tenders were built with means to reach the locomotive from the train through a narrow passageway inside the tender tank plus a flexible bellows [[Corridor connection|connection]] linking it with the leading coach. The passageway, which ran along the right-hand side of the tender, was {{convert|5|ft|m|2}} high and {{convert|18|in|m}} wide. Further corridor tenders were built at intervals until 1938, and eventually there were 22; at various times, they were coupled to engines of classes [[LNER Gresley Classes A1 and A3|A1, A3]], [[LNER Class A4|A4]] and [[LNER Class W1|W1]], but by the end of 1948, all were running with class A4 locomotives.<ref>{{cite book |last1=Boddy |first1=M.G. |last2=Fry |first2=E.V. |last3=Hennigan |first3=W. |last4=Proud |first4=P. |last5=Yeadon |first5=W.B. |editor-last=Fry |editor-first=E.V. |title=Part 1: Preliminary Survey |series=Locomotives of the L.N.E.R. |date=July 1963 |publisher=[[Railway Correspondence and Travel Society|RCTS]] |location=Potters Bar |pages=64–65 }}</ref><ref>{{cite book |last1=Boddy |first1=M.G. |last2=Neve |first2=E. |last3=Yeadon |first3=W.B. |editor-last=Fry |editor-first=E.V. |title=Part 2A: Tender Engines - Classes A1 to A10 |series=Locomotives of the L.N.E.R. |date=April 1973 |publisher=[[Railway Correspondence and Travel Society|RCTS]] |location=Kenilworth |isbn=0-901115-25-8 |page=68 }}</ref> Use of the corridor tender for changing crews on the move in an A4 loco is shown in the 1953 British Transport film ''[[Elizabethan Express]]'', the name of another London-Edinburgh non-stop train. The [[London Midland and Scottish Railway]] also possessed a solitary corridor tender from the late 1940s onwards, built purely for purposes of mobile locomotive testing using a [[dynamometer car]] etc. rather than to give any operating advantage in revenue earning service. {{clear}}
===Water cart=== [[Image:386 K10.jpg|thumb|A [[Southern Railway (Great Britain)]] locomotive with a "water cart" tender]] The ''water cart'' was a type of high-capacity tender used by the [[London and South Western Railway]] in England. Unlike the usual British six-wheel tender, it was a double-bogie design with inside bearings. This gave it a distinctive appearance because the wheels were very obvious.<ref>{{cite web |url=https://sremg.org.uk/steam/t9class_ten.shtml |title=Drummond T9 "Greyhound" class 4-4-0 Tenders |website=Southern Railway E-mail Group |date=30 December 2009 |access-date=16 March 2012 }}</ref>
===Canteen=== [[File:60019 Bittern with 2nd tender at NRM York.jpg|thumb|[[LNER Class A4 4464 Bittern|"Bittern"]] with second tender at York]] An additional tender which holds only water is called a "canteen" or "auxiliary tender". During the steam era, these were not frequently used. [[Water tank]]s were placed at regular intervals along the track, making a canteen unnecessary in most cases. However, there were times that canteens proved economical. The [[Norfolk and Western Railway]] used canteens with its giant [[2-8-8-2]] Y Class and [[2-6-6-4]] [[Norfolk and Western Railway class A|A Class]] locomotives on coal trains, timed freights, fast freights, and merchandise freights. Use of the canteen allowed one of the [[water stop]]s to be skipped, allowing the train to avoid climbing a hill from a dead stop. Currently, the [[Union Pacific Railroad]] uses two canteens with its steam locomotives [[Union Pacific 844|844]] and [[Union Pacific 4014|4014]] on excursion trains. Virtually all the trackside tanks were removed when steam locomotives were retired. Nowadays, [[fire hydrant]] hookups are used, which fills the tanks much more slowly. The canteens allow for greater range between stops.
Canteens were also used on the [[Trans-Australian Railway]] which crosses the waterless [[Nullarbor Plain]]. In New South Wales these vehicles were called "gins", and were used in the predominantly dry western region and on some branch lines. Now prominently use on heritage excursions due to the lack of places with accessible water points. During the catastrophic 2019-2020 bushfire season, as fires devastated towns near the Rail Transport Museum at Thirlmere, south of Sydney, a diesel locomotive from the museum hauled two gins to help replenish firefighting tanker trucks.
In the United Kingdom, a canteen was used on the preserved ''[[LNER Class A3 4472 Flying Scotsman|Flying Scotsman]]'' during enthusiast excursions in the late 1960s and early 1970s. The [[water trough]]s that had previously supplied long-distance expresses had been removed during [[dieselisation]] of the railway network. On 25 July 2009, ''Bittern'' made a 188-mile run from King's Cross to York non-stop using a second tender. As railways in Britain tend to be much shorter than those in the US, the canteen was not an economical proposition.
===Fuel tender=== [[File:Sct-train-fa-hauled-g-class-geelong.jpg|thumb|[[SCT Logistics]] train with tank car supplying fuel to the locomotives, reducing the number of fuel stops required on the transcontinental journey across Australia]]
Sometimes a tender will be used for a [[diesel locomotive]]. This is typically a tank car with a fuel line that connects to the locomotive and [[Diesel multiple unit|MU]] connections to allow locomotives behind the tender to be controlled remotely. The [[Burlington Northern Railroad]] used fuel tenders in remote territory where fuel was expensive. Diesel fuel could be bought cheaply and loaded into the tender. A common consist was two [[EMD SD40-2]]s with a tender between them. Some of the tenders survived the [[BNSF Railway|Burlington Northern Santa Fe]] merger but retain the black and green BN colors. The [[Southern Pacific Railroad]] also briefly experimented with fuel tenders for diesels. Some [[slug (railroad)|slugs]] have fuel tanks and serve as fuel tenders for the attached locomotives, especially those that are converted from locomotives that are retired due to worn-out diesels.
The [[Union Pacific Railroad]] used fuel tenders on its [[Union Pacific GTELs|turbines]]. These tenders were originally used with steam locomotives, then reworked to hold heavy "Bunker C" fuel oil. Fuel capacity was about {{convert|23,000|USgal|liter|abbr=off|sp=us}}. When the turbines were retired, some of the tenders were reworked to hold water, and employed as canteens for steam locomotives.
Fuel tenders have also been the cause of controversy for railroads, in particular{{citation needed|date=October 2023}} the Soo Line. In the late 1970s, the management of the railroad discovered that it was cheaper for them to fill their fuel tenders at Chicago, and then transport the fuel to Shoreham Wisconsin. Doing this avoided the railroad needing to pay extra taxes on the fuel, and the system was continued until the mid-1980s. When the states of [[Illinois]] and [[Wisconsin]] caught onto the railroad's actions, legislation was passed which charged the same over the road tax on the fuel movement over rail which was charged for truck drivers. Doing this completely negated the benefit of moving the fuel by way of the tenders, and Soo quietly withdrew the practice.
Tenders have also been developed to carry [[liquefied natural gas]] for diesel locomotives converted to run on that fuel.<ref name='gastender08'>{{cite web |url=http://www.energyconversions.com/tender.htm |title=Fuel Storage - LNG Locomotive Tender Car |access-date=2008-08-20 |publisher=Energy Conversions, Inc. |archive-date=2015-09-25 |archive-url=https://web.archive.org/web/20150925080638/http://www.energyconversions.com/tender.htm |url-status=dead }}</ref>
===Brake tender=== On [[History of rail transport in Great Britain|British railways]], brake tenders were low, heavy wagons used with early main line [[diesel locomotive]]s. One or two were coupled in front or behind the locomotive to provide extra braking power when hauling unfitted or partially fitted freight trains (trains formed from wagons not fitted with automatic brakes).<ref name=Larkin>''BR Standard Freight Wagons - A Pictorial Survey'', David Larkin, D. Bradford Barton Ltd, 1975, p.61, {{ISBN|0-85153-240-3}}</ref><ref name=SEMG-dbt>{{cite web |url=https://sremg.org.uk/diesel/dbt.shtml |title=Diesel Brake Tenders |website=Southern Railway E-mail Group |access-date=15 March 2009 |date=10 December 2002 }}</ref> They were required as the lighter weight of the new diesel locomotives, compared to steam, meant that they had comparable tractive effort (and thus train hauling capacity) but less braking ability.<ref name="Clough" >{{Cite book |title=Hydraulic vs Electric: The battle for the BR diesel fleet |last=Clough |first=David N. |publisher=[[Ian Allan Publishing|Ian Allan]] |year=2011 |isbn=978-0-7110-3550-8 |page=137 }}</ref> Originally intended to be used in North East England, where they were usually propelled (pushed) by the locomotive, and later used in other regions. On the [[Southern Region of British Railways|Southern Region]] they were normally hauled behind the locomotive.<ref name=Larkin/>
The tender took the form of a hollow box, low enough to avoid obscuring the driver's view when pushed. The body was carried on a pair of former carriage bogies, which provided the automatic brakes.<ref>{{cite web|title=Modelling Diesel Brake Tenders|url=http://www.luddite.me.uk/modelling/dbt.asp|access-date=3 November 2011|archive-url=https://web.archive.org/web/20111006195935/http://www.luddite.me.uk/modelling/dbt.asp|url-status=live|archive-date=6 October 2011}}</ref> The body was filled with scrap steel to raise the weight of the vehicle to {{frac|35|1|2}}–{{frac|37|1|2}} tons; consequently increasing the available brake force.<ref name=SEMG-dbt/> Four lamp brackets were provided at each end to display locomotive headcode discs describing the class of train – when propelled, the tender obscured the front of the locomotive, and hence the headcode.
[[File:Brake Tender coupled to BR Class 25 diesel-electric locomotive.jpg|thumb|Newly built replica Brake Tender is coupled to ex-BR Class 25 diesel-electric locomotive at the [[Great Central Railway (heritage railway)|Great Central Railway]], Loughborough, photographed in 2018]] Introduced around 1964–65, they were taken out of use in the 1980s when the practice of using unfitted trains was discontinued. None survived in preservation but an operational replica has been constructed on the [[Great Central Railway (heritage railway)|Great Central Railway]] from the remnants of a Mk1 corridor coach and has been given the next number in the brake tender sequence; B964122.<ref>{{Cite web|url=http://www.gcrailway.co.uk/2017/11/the-diesel-brake-tender/|title = The Diesel Brake Tender | Great Central Railway – the UK's Only Main Line Heritage Railway}}</ref>
In North America, brake tenders were often referred to as '''brake sleds''', and were conversely primarily used around railroad yards or larger, rail-served industries. Several railroads used brake sleds in and around hump yards, including the [[Southern Pacific Railroad]]<ref>{{Cite web|url=http://espee.railfan.net/sp_brake-sleds.html|title = exTrain Master Brake Sled SPMW 9100}}</ref> and [[St. Louis–San Francisco Railway]].<ref>{{Cite web|url=https://frisco.org/mainline/2014/08/05/h-10-44-281-and-brake-sled-x82/|title = H-10-44 281 and Brake Sled X82}}</ref> Many of these were converted from redundant steam locomotive tenders, and some from redundant locomotives - however, unlike [[Slug (railroad)|slugs]], these did not retain traction motors.
===Powered tender=== Certain early British steam locomotives were fitted with powered tenders. As well as holding coal and water, these had wheels powered from the locomotive to provide greater tractive effort. These were abandoned for economic reasons; railwaymen working on locomotives so equipped demanded extra pay as they were effectively running two locomotives. However, the concept was tried again on the [[Ravenglass and Eskdale Railway]]'s ''River Mite'', and the [[Garratt locomotive]] may be seen as an extension of this principle. Powered tenders were also seen on the [[triplex locomotive]]s in the United States, but these experiments were not considered successful due to the varying mass of the tender. Powered tenders were used extensively on geared logging steam locomotives like the [[Shay locomotive|Shay]], [[Climax locomotive|Climax]], and [[Heisler locomotive|Heisler]] types where the steep grades and heavy trains necessitated the extra tractive effort.
Nowadays, slugs are used with [[diesel-electric locomotive]]s. The slug has [[traction motor]]s that draw electricity from the locomotive's [[prime mover (locomotive)|prime mover]] to provide extra [[traction (engineering)|traction]].
===German practice=== In Germany, attention was given to ensuring that tender locomotives were capable of moderately high speeds in reverse, pushing their tenders. The numerous [[DRB Class 50]] ([[2-10-0]]) locomotives, for example, were capable of {{convert|80|km/h|mph}} in either direction, and were commonly used on [[branch line]]s without turning facilities.
A source of possible confusion with regards to German locomotives is that in [[German language|German]], ''{{lang|de|Tenderlokomotive}}'' means a tank locomotive. A locomotive with a separate, hauled tender is a ''{{lang|de|Schlepptenderlokomotive}}''.
==Tender-first operations== [[File:46443 Ivatt at Bewdley station.JPG|thumb|right|200px|Preserved [[LMS Ivatt Class 2 2-6-0]] no. 46443 at [[Bewdley railway station|Bewdley]] on the [[Severn Valley Railway]]. The front of the tender has a half-cab for tender-first running.]]
In some instances, particularly on branch lines having no turnaround such as a [[railway turntable|turntable]] or [[Wye (rail)|wye]] at the terminus point, locomotives ran in reverse with the tender leading the train. In such instances, a headlamp (US) or headcode lamps/discs were placed on the leading end of the tender. Locomotive crews often rigged a [[tarpaulin]] (or the locomotive's storm sheet, if available) from the rear of the cab roof to the front of the tender to provide protection from the wind and to prevent coal dust being blown into the cab. Tenders designed for more frequent tender-first workings were often fitted with a fixed cab panel and windows, providing an almost fully enclosed cab.
== See also == * [[Coal bin|Coal bunker]]
==References== {{Reflist}}
== Further reading == *{{Cite magazine |first=David |last=Lustig |date=2023-10-16 |title=Steam locomotive tenders have a life of their own |url=https://www.trains.com/trn/train-basics/abcs-of-railroading/steam-locomotive-tenders-have-a-life-of-their-own/ |access-date=2023-10-17 |website=Trains |language=en-US}}
== External links == {{commons category|Steam locomotive tenders}} {{commons category|Diesel brake tenders}} *[http://www.steamlocomotive.com/types/tenders/ United States locomotive tenders]
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