I just had an idea. I know i brought up the idea about the tanker and limited water supplies but it would just add frustration to the game, so, i thought of another idea for the usage of the tanker. You can use it to connect fire hoses but it doesn't carry any equipment. It should be able to carry one or two fire fighters or even none. The tanker should be used for those difficult terrains where there are no fire hydrants and you have spare fire fighters in your Engine. You would just grab a hose from your Engine and connect to the Tanker