Color Position Lights To provide some background on my relationship to the color position light, let me go back in time a bit here.
As a teenager I used to drive down to the Baltimore & Ohio Railroad in southern Indiana to chase trains. As far as I know, the B&O, and the Chicago & Alton (which was controlled by the B&O), later the GM&O, were the only roads to use this particular signal type. (Though, it should be said, there are similarities to a later Pennsylvania Railroad signal type that can still be found on the Northeast Corridor.) The color position light was developed by superintendent of signaling of the B&O, Frank Patenal, around 1918 (source). The signals are favorites of rail enthusiasts for their complex and rich appearance. The “position” of the CPL mimics that of upper-quadrant semaphores that came before them. The “color” of the CPL adds another layer of information to reinforce the indication.
Simplifying here, the most common indications are—clear (or proceed), approach (or proceed at restricted speed), and stop. The additional “marker lights” (above or below) can alter the simple indication to modify speed or indicate a diverging route, etc.
In any event, most signal systems around the United States have been replaced with one type, the color light—with separate green, yellow, and red lights positioned one over the other. To make matters worse, the signal is typically covered by a large sun- and snow-shade, hiding any of its inherent charms, which are non-existent anyway.
The first picture here shows a westbound B&O train at Wheatland, Indiana, on the former Ohio & Mississippi (originally built as broad gauge); the line runs between Cincinnati and St. Louis. The second image shows a southbound train on the former Alton, just north of Lincoln, Illinois. The final photograph, a simple portrait of the pair of signals, is again at Wheatland.
All images by Richard Koenig. The two black & white images, made along the B&O, were taken on March 7th 1976, while the GM&O image was made on November 21st 1976.
