OAM Functionality for MPLS Networks

A transport apparatus has a loading ramp pivotally connected to a lower frame, which is supported for transport along the ground. The ramp also is pivotally connected to an upper frame, which is disposed above the lower frame and connected thereto by linkage means. The vertical distance between the pivotal connections of the ramp to the lower frame and the upper frame, the horizontal distance between the pivotal connection of the ramp to the lower frame and the pivotal connection of the linkage means to the lower frame, the length of the linkage means between its pivotal connections to the upper and lower frames, and the horizontal distance between the pivotal connections of the linkage means to lower and upper frames are selected so that the horizontal force exerted at the pivotal connection of the ramp to the upper frame is greater than the horizontal force exerted at the pivotal connection of the linkage means to the upper frame when the ramp is in a ground engaging position to hold the ramp in this position until a load is driven up the ramp onto the upper frame. These various distances also are selected so that the ramp will remain in a transport position after the load has been advanced onto the upper frame.