Abstract: The locking fuel nozzle is used to prevent spilling of fuel while filling two-inch fill tubes on railroad cars. The nozzle includes a nozzle tube that is secured to a pressurized fuel source. The nozzle tube is inserted into the opening of the fill tube and delivers fuel from the pressurized fuel source to a fuel receptacle. A sealing member is disposed along the nozzle tube. A compression member is slidably disposed along the nozzle for impacting the sealing member. A handle is secured to the compression member for forcing the compression member along the nozzle tube. The compression member compresses the sealing member forcing it to swell. The sealing member swells until it completely seals the opening of the fill tube and the compression member is then locked into place by the handle.