A The second tender you ask about is generally referred to as an “auxiliary tender,” and also as a “canteen” or a “water car.” As the name implies, second tenders are often used to increase the supply of water that a steam locomotive has to draw from between water stops. The locomotive and tender are connected with the same sort of hoses, couplings, and valves that are used to connect a locomotive to a “first” tender. In the steam era, the auxiliary tender was used to reduce or eliminate water stops between terminals. In the fantrip era, auxiliary tenders are used because many water tanks and water columns that would have provided a large volume of water for a thirsty locomotive, have been removed. — J. David Conrad, chief mechanical officer, The Valley Railroad Co.
