This species' common name refers to its resemblance to railway semaphore signals.

The first railway semaphore signals had arms that could be worked to three positions, in the lower quadrant.

Finally, with no one else left, Marcus himself is struck on the head by a railway semaphore signal over the tunnel, and drops lifeless into another wagon.

The first railway semaphore signal was erected by Charles Hutton Gregory on the railway at New Cross, about 1842.

A railway semaphore signal is designed so that should the cable controlling the signal break, the arm returns to the "danger" position, preventing any trains passing the inoperative signal.

If it was raised too early there was a chance of hitting and destroying switch targets, telegraph poles, and railway semaphore signals, as well as the train's mail catcher arm.