Heat is provided by the firebox to make steam. The firebox is surrounded by the boiler's barrel and topped with the crown sheet, where the feedwater is converted to usable steam and siphoned into the boiler tubes. The firebox consists of a combustion chamber divided by the "brick arch" (which bisects the firebox and creates improved drafting, allowing use of wood, coal, or oil, instead of coke as a viable fuel), the crown sheet, and the grate on which the burning coal is supported.
Quick facts
Coal makes difference
Easy manufacture
Improving combustion
First use in England
Large locomotives