Trams and electric trains are often powered from overhead electric wires. The parallelogram-shaped connecting mechanism is called a pantograph. In fact, more commonly, these days a half-pantograph is used. The word ‘pantograph’ comes from the Greek panto = all, and graph = to write. So why is this name given here? Well, for many years a similar pivoted and slightly extended parallelogram mechanism was used by architects and draughtsmen to make enlargements of their drawings. Before the days of photocopiers!
