A monorail's a rail-based transportation system based on a single rail, which acts as its sole support and its guideway. The term's also used variously to describe the beam of the system, or the vehicles traveling on such a beam or track. The term originates from the contraction of the words mono (single) and rail, from as early as 1897, as early systems used metal rails. The transportation system's often referred to as a railway. In contrast, a light rail system has two rails sharing support o… (More on Monorail)