Abstract: The straddle apparatus for loading and unloading gondola and similar-type railcars is mobile for movement into a position straddling a railcar on railroad tracks. It has a platform supported by leg members adjustable to vary the elevation of the platform above the railcar. A boom mount structure is fixed to the front portion of the platform. Stabilizing assemblies are also mounted at the front edge of the platform for swinging downwardly to abut upper surface lateral edges of the railcar with an operator-selected degree of pressure to reduce lateral wobble movement and longitudinal roll movement of the railcar during loading and unloading operations. The stabilizing assemblies also give additional support to the boom assembly during the material handling operations of loading and unloading.