A fuel system for a vehicle is provided. The fuel system is configured to couple to a frame rail of the vehicle. A fuel system frame assembly of the fuel system is configured to couple with the frame rail directly or with another component that is coupled, directly or indirectly, with the frame rail. A cowling of the fuel system can include a fuel pressure vessel. The fuel pressure vessel configured to be placed within and supported by the fuel system frame assembly. The fuel system is configured to enhance component arrangement efficiency when mounted to a vehicle frame rail.