When a trolley passes over the upper bend of a vertical curve, it imparts to the rail and trolley a force greater than the load being carried. Chain pull, trolley spacing and vertical curve radius are factors influencing the magnitude of this force.

Table 8 presents data to be applied to determine the thrust load. Layout and design alterations may be necessary to insure that trolley reactions on the rail are not excessive. Table 9 indicates maximum recommended radial load per two-wheel trolley.