A fireman, stoker or watertender is a person whose occupation it is to tend the fire for the running of a boiler, heating a building, or powering a steam engine. Much of the job is hard physical labor, such as shoveling fuel, typically coal, into the boiler's firebox.^[2] On steam locomotives the title fireman is usually used, while on steamships and stationary steam engines, such as those driving saw mills, the title is usually stoker (although the British Merchant Navy did use fireman). The German word Heizer is equivalent and in Dutch the word stoker is mostly used too. The United States Navy referred to them as watertenders.

The Royal Navy used the rank structure ordinary stoker, stoker, leading stoker, stoker petty officer and chief stoker. The non-substantive (trade) badge for stokers was a ship's propeller. Stoker remains the colloquial term used to refer to a marine engineering rating, despite the decommissioning of the last coal-fired naval vessel many years ago.

Large coal-fueled vessels also had individuals working as coal trimmers, who delivered coal from the coal bunkers to the stokers. They were responsible for all coal handling with the exception of the actual fueling of the boilers.

The Royal Canadian Navy had coal-fired ships, the last of which were replenishment ships. All marine engineers in the RCN, regardless of their platform (CPF, 280 or AOR) are nicknamed stokers.

In the United States Navy, watertender (abbreviated WT) was a petty officer rating which existed from 1884 to 1948. Watertenders held a paygrade equivalent to today's petty officer first class. A chief watertender (CWT) paygrade was established in 1903. In 1921, the lower paygrade was split into watertender first class (WT1 or WT1c) and watertender second class (WT2 or WT2c). Another lower paygrade, watertender third class (WT3 or WT3c), was established in 1943. The watertender and boilermaker ratings were merged into a new "Boilerman" rating in 1948 and continued to 1976 when the rating was changed to "Boiler Technician" and subsequently merged into the "Machinist's Mate" rating in 1996.^[3][4][5]

On steam locomotives, firemen were not usually responsible for initially preparing locomotives and lighting their fires. As a locomotive boiler takes several hours to heat up, and a too-rapid fire-raising can cause excess wear on a boiler, this task was usually performed by fire lighters working some hours before the fireman's main shift started. Only on small railways, or on narrow-gauge locomotives with smaller and faster-warming boilers, was the fire lit by the fireman.

Whoever was responsible for fire-starting would clear the ash from the firebox ashpan prior to lighting the fire, adding water to the engine's boiler, making sure there is a proper supply of fuel for the engine aboard before starting journeys, starting the fire, raising or banking the fire as appropriate for the amount of power needed along particular parts of the route, and performing other tasks for maintaining the locomotive according to the orders of the engineer (US) or driver (UK). The engine itself was cleaned by an engine cleaner instead of the fireman.^[2] Some firemen served these duties as a form of apprenticeship, aspiring to be locomotive engineers themselves. In the present day, the position of fireman still exists on the Union Pacific Railroad, but it refers to an engineer in training. The fireman may operate the locomotive under the direct supervision of the engineer. When the fireman is not operating the locomotive, the fireman assists the engineer and monitors the controls. ^[6]

A mechanical stoker is a device which feeds coal into the firebox of a boiler. It is standard equipment on large stationary boilers and was also fitted to large steam locomotives to ease the burden of the fireman. The locomotive type has a screw conveyor (driven by an auxiliary steam engine) which feeds the coal into the firebox. The coal is then distributed across the grate by steam jets, controlled by the fireman. Power stations usually use pulverized coal-fired boilers.

Vladimir Lenin, disguised as Konstantin Petrovich Ivanov, escaped to Finland in 1917 on train 293 from Udelnaya Station. Guro Jalava, a co-conspirator and the train's driver, helped to further conceal Lenin by having him work as his stoker. Jalava later recalled that Lenin shovelled with gusto as he fed the engine, making the train run fast.^[7]

There were approximately 176 stokers on board the coal fed ocean liner RMS Titanic. During the sinking of the ship, these men disregarded their own safety and stayed below deck to keep the steam driven electric generators running for the radiotelegraph, lighting, and water pumps.^[8][9][10] Only 48 of them survived.^[11]

Simeon T. Webb was the fireman on the Cannonball Express when it was destroyed in the legendary wreck that killed engineer Casey Jones. Jones's last words were "Jump, Sim, jump!" and Webb did jump, survived, and became a primary source for information about the famous wreck.^[12][13]

KFC founder Colonel Sanders worked as a railroad stoker when he was 16 or 17.^[14]

A 14-year old Martin Luther King Sr. worked as a fireman on the Atlanta railroad. ^[15]