An improved monorail-type track section for use in a material handling and sortation system in which one or more train-type trolleys or cars runs along the track between various sortation and handling stations. The track section comprises a substantially hollow, vertical support member terminating at an upper end in an upper transverse leg defining upper wheel bearing surfaces on each side of the support, and terminating at a base end in a transversely extending base leg defining lower wheel bearing surfaces on each side of the vertical support. The upper and lower wheel bearing surfaces are angled to trap upper and lower wheel assemblies on a trolley in a torsionally stable mounting arrangement. The spacing of the upper wheel bearing surfaces is less than that of the lower wheel bearing surfaces, such that removal of the upper wheel assemblies allows the entire trolley to be lifted vertically off the track section with clearance for the lower wheel assemblies.