 A fireless locomotive eliminates this danger—if it runs out of sufficient water, it simply ceases to move—although precautions must be taken as with any other pressure vessel.Furthermore, they do not require careful monitoring of water levels and boiler pressure, or careful distribution of coal in the firebox for efficient combustion, and thus can be operated by less-skilled staff, not requiring a fully qualified locomotive engineer and fireman.Several locomotive builders produced fireless engines throughout the 20th century.