| Here is another view of Richmond, Fredericksburg & Potomac 4-8-4 #619 wearing the "Automatic Train Control" sign denoting the use of Pulse Code Cab Signal system designed by Union Swithc & Signal in 1922 for stopping trains. This early, simplistic system is the forerunner of the modern Postive Train Control system of today. The system is failsafe in that the lack of code would display a Restricting signal. The codes would be transmitted to the train from the block limit in front of it. This way if the rail was broken or another train entered the block, any codes would not reach the approaching train and the cab signal would again display Restricting. No date or photographer was listed for this photo. |
| Date:
6/1/1950 |
Location:
Alexandria, VA Map  |
Views:
221 |
Collection Of:
 
Gary Everhart |
| Locomotives: |
Author: Gary Everhart
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| Picture Categories: Roster,Yard,Steam |
This picture is part of album: RFP "Pulse Code Cab Signal" |