Loco Firing

The Fire Triangle

The fire triangle is used by fire fighters to show that there are 3 components which, if all present & balanced, will cause a chemical reaction - a fire.   Remove a component and the fire goes out.   The inverse applies to steam loco firing, where the fireman must strive for the perfect balance of components to get the most heat energy from coal, which also occurs with minimum smoke.

Heat is the most important component to fully burn coal, which ignites at about 600C, but burns efficiently at about 1400C.   A skilled fireman raises the fire temperature smartly & maintains it as near as possible to 1400C by feeding air & coal appropriately.

Tanfield Railway currently uses smokeless coal from Ffos-y-Fran opencast mine at Merthyr Tydfil.   It's a soft, carbon-rich coal which needs more heat than others to ignite & release most energy with least smoke.   It has an ash content of  about 7%, which remains after the coal burns.   If this ash is cooled rapidly it clinkers and sets on anything relatively cold - we use dolomite so that the clinker sets on the cooler dolomite rather than the firebars.

BTC Good Firemanship 1956 booklet

The British Transport commission produced a booklet for BR fireman at a time of transition to diesel locos & a shortage of steam crews.   It notes that it is expected that coal will become less available & more expensive - in the 1950s!   This prediction is even more true today - plus we face public pressure to eliminate use of non-renewable hydrocarbon fuels.   We need to reduce use of coal, & when we use it, burn it as efficiently as possible.

Tanfield Railway locos have small fireboxes, with short runs between stations and steep inclines, although our loads are light & speeds low.   Fireman have to use blower, damper, firehole door, the scope of the water in the gauge glass, but above all shovel coal little & often to maintain a hot firebed.   
The Kent & East Sussex Railway publishes several useful MIC documents on line - see in particular Combustion & Heat and Steam.   Other railway publish similarly, & in due course TR intends to publish materials more particular to our size of locos & line.

Footnotes: for more on coal formation & geology, see Fossil Fuels, but note that in the US the carboniferous period is termed Pennsylvanian & Mississippean.   Due to the earth's formation & geology, the largest deposits of fossil fuels are in Russia.   The reasons the UK was an early user of fossil fuel include the need to conserve wood for warships, "easy" coal production in & transport from NE England to satisfy the huge market in SE England, and parallel developments in science & technology.