A tractor truck configured for towing trailers of different air connection configuration. The truck has a first and a second tractor protection valve, each configured to be located on the tractor at a location remote from the other. Each tractor protection valve location is proximate a typical position at which a mating connection on a trailer will be located when hitched to the tractor. The truck also has a selector which is operator-transitionable between a first configuration in which the first tractor protection valve is activated to supply pressured air to an interconnected trailer and a second configuration in which the second tractor protection valve is activated to supply pressured air to a different interconnected trailer.