What Is This?

What Is This?. A Railroad Semaphore. , A semaphore is a device used to signal the engineer of a train with information about the speed they should travel and, sometimes, the route they should take. This information is conveyed by the position of the arms (day) and colored lights (night) on the semaphore., Clear (Proceed), Approach (Prepare to stop at next signal, reduce speed), Stop (Stop, then proceed at restricted speed until entire train passes next signal),

. Semaphore signals were first developed for railroad use in England during the 1840's. , . They allowed information to be transmitted to the engineer of a moving train. , . Supplanted earlier technologies involving flags, balls, vanes, banners and disks. , . Originally powered by levers or compressed air and lit with kerosene lamps. , . Primarily electrically powered by the early 20th century. , . They were displaced by electric light signals beginning in the late 1920's.

, [1st photo at left:] , A 1984 photogrnph of this semaphore in its original location on the B&O Railroad. , Photo: Mike Closek from a film by Steve Jensen , [2nd photo at left:] , photo: Aaron J. Border , [1st photo at right:] , Platform [,] Mast [,] Ladder [,] Foundation , [2nd photo at right:] , Pinnacle [,] Roundels [,] Blade [,] Mechanism [,] Spectacle [,] Lamp , [sketch at lower right:] , Design: Betsy Molina Mortensen, The Anatomy of a Semaphore , A semaphore consists of a pole or other support structure with one or more movable arms called "Blades." The position of the blades convey[s] a specific piece of information to the train crew. For night use, colored lenses or roundels are held in "spectacles" attached to blades that are moved in front of a lantern. Additional information was conveyed by the shape and color of the blades or the presence of additional "marker" lights or signs on the pole. Each combination of blade positions, colors, shapes, lights and markers is called an "aspect” and the message it represents an indication.” The indication might be about the presence of another train ahead, the speed or speeds the engineer should employ on upcoming track, the route to be expected through an upcoming series of switches. or the need to obtain train orders. Knowing all the possible semaphore aspects and what each indicated for a particular railroad was a required skill for engineers, firemen, conductors and brakemen - just as it remains today with modern signal systems., This semaphore is original to the Baltimore and Ohio Railroad and was used on tracks in Wilmington, Delaware from 1920 to 1985., -Adapted from an original article by Mark Sylvester, Partial funding for restoration supplied by , National Railway Historical Society , and the Amherst Railway Society, Inc.. , Wilmington and Western Railroad , wwrr.com