A method for dewatering an operating substance, more particularly a fuel, preferably during the operation of a vehicle, more particularly a rail vehicle, includes conveying an operating substance from an operating substance tank. Water present on or in the fuel is first collected in a water container, and water is conveyed, in chronological order, from the water container back to the operating substance tank, then to an exhaust system and/or from the operating substance tank to the exhaust gas system. A dewatering device for an operating substance, more particularly a fuel for a vehicle, more particularly a rail vehicle, includes a water container, in which water present on or in the fuel is collected. The dewatering device has a dewatering conduit or line which runs from the water container to an operating-substance tank of the vehicle and/or to an exhaust-gas system of the vehicle.

A tank assembly includes a tank having a plurality of tank walls surrounding an interior cavity. The interior cavity is configured to store a fluid. The fluid is configured to expand upon a change in temperature. A fill channel and a vent channel are each in fluid communication with the interior cavity. At least one compressible member is positioned within the interior cavity and configured to provide an expansion space for the fluid. The compressible member eliminates the need to be concerned with a loss of air space when filling the tank with low flow rates and when filling on grades. The compressible member may be composed of a closed cell foam material. Alternatively, the compressible member may include a pouch having a hollow space surrounded by an outer skin.

Embodiments of a fluid tank may comprise suction tube system that comprises a floating suction tube useful for filling or removing a fluid from the tank. Further in some embodiments, the tank system may be installed in a single port on the fluid tank. A buoyant portion of the suction tube can be constantly submerged in a desired portion of the fluid, allowing the desired fluid to be removed through the inlet port. A level indicator system may include a cable system connected between a biased level indicator that moves in conjunction with the movement of the buoyant portion to indicate the fluid level.

Embodiments of a fluid tank may comprise a suction tube system for use in tanks, particularly in gas stations and backup generator applications. The system includes a flexible, elastic suction tube designed to bend and unbend as fluid levels change within the tank. A float connected to the flexible tube is designed to position the intake above water at the bottom of the tank and in the clean portion of the fluid. The intake is positioned between the terminal end of the float and the flexible tube to maximize fuel purity.