Greenville in Mercer County, Pennsylvania — The American Northeast (Mid-Atlantic)

Position Signal Light

Photographed By Cosmos Mariner, June 15, 2021

1. Position Signal Light Marker

Inscription. This is a position signal light. If three lights were lit vertically, a train could proceed. Three lights horizontally meant stop. Three lights diagonally allowed a train to proceed at a reduced speed, prepared to stop at the next signal.

This signal light came off the Union Railroad, which serviced all the steel mills of US Steel in the Monongahela Valley.

This was donated by the Fuddy Duddy’s Club,
a group of Union Railroad retirees who were big supporters of the Greenville Railroad Park in its early days.

Topics. This historical marker is listed in these topic lists: Communications • Railroads & Streetcars.

Location. 41° 24.478′ N, 80° 22.867′ W. Marker is in Greenville, Pennsylvania, in Mercer County. Marker can be reached from the intersection of Main Street (Pennsylvania Route 358) and Union Street, on the right when traveling west. Marker and position signal light are located on the Greenville Railroad Park & Museum grounds. Touch for map. Marker is at or near this postal address: 314 Main Street, Greenville PA 16125, United States of America. Touch for directions.

Other nearby markers. At least 8 other markers are within walking distance of this marker. Railroad Crossing Lights (here, next to this marker); Switch Stand (a few steps from this marker); Wreck Train Chain (a few steps from this marker); Bessemer Caboose #1985

Paid Advertisement

Click on the ad for more information.
Please report objectionable advertising to the Editor.

Click or scan to see
this page online

(a few steps from this marker); Štefan Banič (a few steps from this marker); Bessemer Ore Jenny #20567 (within shouting distance of this marker); Union Pacific Caboose #25437 (within shouting distance of this marker); Erie 40' Flatcar #8200 (within shouting distance of this marker). Touch for a list and map of all markers in Greenville.

Related markers. Click here for a list of markers that are related to this marker. Greenville Railroad Park & Museum

Also see . . . Position Light Signals.

A position light signal is one where the position of the lights, rather than their color, determines the meaning of the aspect that's being conveyed to the Engineer or other designated employee. The aspect consists solely of a pattern of illuminated lights, which are all of the same color (typically amber or white). This had the advantage of eliminating any and all effects of even slight color blindness by the train crew. (The Pennsylvania Railroad found that 1 in 3 engineers were color blind.) The PRR chose to use their Superintendent of Signaling, A.H.Rudd's, in-house developed position light signals to both replace
Photographed By Cosmos Mariner, June 15, 2021

2. Position Signal Light
(marker is mounted on building in background)
the semaphores and their moving parts, also because the intense lemon-yellow light provided superior visibility in adverse weather conditions such as rain, fog or snow.

(Submitted on February 3, 2022, by Cosmos Mariner of Cape Canaveral, Florida.)

Position Signal Light image. Click for full size.

Photographed By Cosmos Mariner, June 15, 2021

3. Position Signal Light

Credits. This page was last revised on February 3, 2022. It was originally submitted on February 3, 2022, by Cosmos Mariner of Cape Canaveral, Florida. This page has been viewed 121 times since then and 17 times this year. Photos: 1, 2, 3. submitted on February 3, 2022, by Cosmos Mariner of Cape Canaveral, Florida.