High Quality Content by WIKIPEDIA articles! A tender or coal-car is a special rail vehicle hauled by a steam locomotive containing the locomotive`s fuel (wood, coal, or oil) and water. Steam locomotives consume large quantities of water compared to the quantity of fuel, so tenders are necessary to keep the locomotive running over long distances. A locomotive that pulls a tender is called a tender locomotive. Locomotives that do not have tenders and carry all their fuel and water on board the locomotive are called tank engines.