Abstract: A farm tractor or the like including an engine situated at a forward end of the tractor substantially above the front wheel axle and a gear box situated at a rearward end of the tractor. A fuel tank is fitted between the engine and the gearbox, the fuel tank comprising an elongate box-beam shaped member constituting a load carrying part of the supporting frame assembly of the tractor and extending over a substantial part of the length thereof. The fuel tank includes a body forming wall defining a substantially single curved surface generated by a generatrix which is substantially parallel to the longitudinal direction of movement of the tractor. The body forming wall is constituted by a formed sheet of metallic material and a pair of substantially planar end members are fixed to the ends of the fuel tank body.