Love the fight between 'tanker' and 'tender'! How's this: tender (CONTAINER) noun
a vehicle used for transporting water, wood or coal, especially one which is pulled behind a railway engine or used by the fire service, or a small boat used for transporting people or goods between a larger boat and the coast
(coutesy of Cambridge University dictionary)
The only 'tenders' I know of out here are the small boat kind. As a Fire Service, we have tankers alright! But they're fire fighting vehicles, not bulk water carriers - when we need that sort of tanker we hire commercial ones.
It's a firefighting vehicle! When we need bulk water transport we bring in the semi milk tankers and draft from them. Works for us.
Road Trains are used for any sort of bulk haulage in central and northern Australia. But not near any of the major cities! When driving on one of the outback roads - the unmade back roads - if you see one of those things coming the best action you can take is to slow down, do a 90 degree turn, and head off into the scrub away from the road! They have right of weight.
We have a converted Military fuel tank trailer its 5000 gallons we pull it with a Freightliner truck. This is the only pic i have on the computer sorry.
This is a Tatra Tender S&S is building for the BLM it comes in a wildland unit and a tanker and 2000 to 3000 gallons we build the the tanks for these trucks.