The invention relates to the loading of mail bags from a loading dock into an end loading highway vehicle to fully and completely load the vehicle, in one form of which a pair of tandem connected conveyors are mounted on the loading dock for running under existing mail bag handling conveyors, that are proportioned lengthwise, and are mounted to be moved into the vehicle for loading purposes, to extend between the existing conveyor where there is one, and if not, the loading dock, and the desired unloading point of the bags within the vehicle. The bags are moved single file down the conveyors, with the leading conveyor end being upwardly and laterally movable relative to a baffle member connected thereto that extends transversely of vehicle. The conveyors accelerate the bags up to propelling speed whereby they are propelled forwardly of the conveyor discharge end and against the vehicle end wall to fall behind the baffle member which serves to dam the bags against any substantial rebound. In another form the tandem connected conveyors are in sections carried by a wheeled frame, which is provided with a forward conveyor section for swinging movement about a horizontal axis adjacent its rearward end for elevational distribution of the mail bags, and that carries a high speed bag propelling belt conveyor equipped with a bag damming baffle member of a roll up type. Associated with the wheeled frame is a second conveyor section having its forward end approximating the elevation of the rearward end of the first conveyor section, and having its rearward end at an elevation for convenient manual loading of mail bags thereon. The second conveyor section includes a belt conveyor operating at a lower speed for conveying mail bags received thereon to the high speed propelling conveyor. Both conveyor sections have dimensions transversely thereof that substantially span the transverse dimension of the vehicle loading area.