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White Hall in Harford County, Maryland — The American Northeast (Mid-Atlantic)
 

509 Electrical Light Display Block Signal

Circa 1930

 
 
509 Electrical Light Display Block Signal Marker image. Click for full size.
By Devry Becker Jones, October 11, 2021
1. 509 Electrical Light Display Block Signal Marker
Inscription.  
As railroads developed in the mid-nineteenth century there was a need to control the traffic on the railroads.

The first attempt to control traffic was by the use of the telegraph system. Station Masters would have the normal printed schedules and be informed by a telegraph message of any unexpected changes that occurred. It was their job to inform the crew operating the train of these changes. As traffic continued to increase this method became too slow and cumbersome.

The next big step was the "Block Tower" system. On the Northern Central Railroad almost all of the towers were hexagonal in shape and two stories high. Each of these towers controlled a "Block" or section of track that was three to five miles in length. The controls in the tower where mechanical and operated the local switches and signals by cables that ran through protective chases or troughs. The switches and signals determined which trains had priority for the main tracks and which had to go on the side tracks. They also had controlled the speeds at which the trains were allowed to operate within that block.

In the 1930's electrical
509 Electrical Light Display Block Signal image. Click for full size.
By Devry Becker Jones, October 11, 2021
2. 509 Electrical Light Display Block Signal
Click or scan to see
this page online
control systems, including the 509 electrical light display block signal shown here, began to replace the manually operated signal systems. This allowed for the closure of most of the block towers. As the new system was perfected it greatly improved the efficiency and safety of the railroad. Technology reached the point that the electrical conductivity of the metal rails could be used to determine where trains were on the rail system. By the mid 1950's a single operator was responsible for fifty or more miles of track.

All trains today are controlled and tracked by global positioning systems.
 
Topics. This historical marker is listed in these topic lists: CommunicationsRailroads & Streetcars.
 
Location. 39° 37.291′ N, 76° 37.731′ W. Marker is in White Hall, Maryland, in Harford County. Marker is at the intersection of Torrey C. Brown Rail Trail and Wiseburg Road, on the right when traveling south on Torrey C. Brown Rail Trail. Touch for map. Marker is at or near this postal address: 1415 Wiseburg Rd, White Hall MD 21161, United States of America. Touch for directions.
 
Other nearby markers. At least 8 other markers are within 5 miles of this marker, measured as the crow flies. White Hall (about 300 feet away, measured in a direct line); Torrey C. Brown Rail Trail (about 400 feet away); Flag (approx. 1.2 miles away); Parkton, MD Track Chart (approx. 2.4 miles away);
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Virginia Hall (approx. 3 miles away); Fosters "Masemore" Mill (approx. 3.1 miles away); Black Horse Tavern (approx. 4.1 miles away); Bentley Springs (approx. 4.3 miles away). Touch for a list and map of all markers in White Hall.
 
 
Credits. This page was last revised on October 11, 2021. It was originally submitted on October 11, 2021, by Devry Becker Jones of Washington, District of Columbia. This page has been viewed 54 times since then. Photos:   1, 2. submitted on October 11, 2021, by Devry Becker Jones of Washington, District of Columbia.

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Dec. 7, 2021