Evening Republican, Volume 18, Number 74, Rensselaer, Jasper County, 27 March 1914 — EASILY SEEN BY ENGINEER [ARTICLE]

EASILY SEEN BY ENGINEER

Illuminated Semaphore Signals Tried and Approved by German Railroads.

Illuminated semaphore signals, equally efficient by day as well as by night, have been proposed many times and have been the subject of several patents. The idea has been tried in this country, says the Engineering News, and a signal of this class has been in use for about two and a half years in the classification yard of the Prussian state railways at Tempelhof, near Berlin. It is said that it has given good results in ordinary weather and also during fogs, and that the operating costs are small.

The signal has a long blade or arm pivoted at the middle and bent to a parabolic curve. The blade consists of a long narrow mirror, while a smaller mirror curved in the opposite direction gives the back or reverse indication. In each case, a lamp placed in the focus of the parabola furnishes the illumination. A plat- . form at the top of the signal mast serves for maintenance of mirror and lamp. The large mirror has a focal length of four feet, and other dimensions found,to be the best by experiment. The reflecting face is coated with aluminum-bronze paint but the surface is not polished, as a diffusing action is thought best. A small parabolic reflector behind the lense serves to throw all the light upon the signal arm. ■ The signal is lighted with acetylene gas, fed from a steel tank at the foot of the mast, but any other form of lighting could be used.