Brain cells (also known as "glia" or "neuroglia") come in several types, and perform a number of critical functions, including structural support, metabolic support, insulation, and guidance of development. Neurons, however, are usually considered the most important cells in the brain. The property that makes neurons unique is their ability to send signals to specific target cells over long distances. They send these signals by means of an axon, which is a thin protoplasmic fiber that extends from the cell body and projects, usually with numerous branches, to other areas, sometimes nearby, sometimes in distant parts of the brain or body.
Signals, Crane and Subway, Charters Towers railway station mechanical signals were controlled from signal cabins, which dealt with the traffic on a particular block of railway line. Signal cabins coordinated signals that indicated whether or not a section of track was clear of other traffic. Early signals were mechanical, while later signals were operated electrically. The most common form of mechanical signal was the semaphore signal. These consisted of a metal framed tower with one or more arms that could be inclined at different angles, with the arm at the horizontal signalling "danger", or do not proceed. Mechanical signals were usually worked by a wire cable running from