A fire-tube boiler is a type of boiler invented in 1828 by Marc Seguin, in which hot gases pass from a fire through one or more tubes running through a sealed container of water. The heat of the gases
Sectioned fire-tube boiler from a DRB Class 50 locomotive. Hot flue gases created in the firebox (on the left) pass through the tubes in the centre cylindrical section, which is filled with water, to the smokebox and out of the chimney (stack) at far right. The steam collects along the top of the boiler and in the steam dome roughly halfway along the top, where it then flows into the large pipe seen running forward. It is then divided into each side and runs downward in the