Color Position B&O and Position Pennsy Signals

In the 1920’s, the Pennsylvania Railroad replaced their semaphore signals with a position light type supplied by Union Switch and Signal Co. Although there were several variations in the basic signal employed seven amber lamps, the center one being “on” for each on the three indications. In the mid 1930’s, the B&O decided to replace their semaphore signals with a color position type from General Railway Signal Company. The basic head employed six lamps – two each of red, yellow and green. The B&O system also employed lunar white marker lights for speed indication.

Pennsy and N&W Signals

ISS manufactures the basic seven lamp PRR signal head exactly to HO scale using light yellow 3 mm diameter LEDs. The head can be mast mounted or used on signal bridges. In both cases it was mounted in front of the mast. The ISS signal controller SC-2 will operate these signals using lower value current limiting resistors. The Pennsy also used lower quadrant (or lower head) signals to indicate various speed and track conditions.

ISS has three types of lower quadrant signals available:

PRR_LowerQuadrant_vert_cros PRR_LowerQuadrant_3amber Pennsy-with-Marker-001
The vertical &
cross arrangement
The 3 amber
lamp vertical
A signal amber lamp mounted
in the lower quadrant position


B&O Signals

ISS has available in HO scale the basic six lamp color directional signal employed by the B&O. Again, we are using 3mm diameter LEDs. (The correct scale size would be 2.5 mm, but they are not available.) The heads may be mast or bridge mounted, and our SC-2 signal controller will correctly operate the signals using different values for current limiting resistors as two lamps are always “on”. B&O heads are always bracket mounted in front of the mast which is how we supply them. The service platform extends ¾ in front of the mast and ¼ to the rear of the mast. All B&O signals employ lunar white marker lights, either single or in pairs, above and/or below the main head. These lights indicate the recommended
speed in conjunction with the main head. We supply a special frosted 12 volt bulb installed in a correctly sized single round head to simulate the marker light. The bulb operates at 6.4 to 7 volts for the best effect and long life.