Railroad defect detectors and signaling systems.


Automatic Block Signaling…(ABS)

The basic concept of ABS is that the track is divided into Blocks; sections that are protected by Block Signals. A block is the section of line between two consecutive block signals. Trains operate by a track warrant being given to each train crew that obide by specific rules for each block at Control Points. CP’s are marked with mile markers, as like with hiway mile markers, thus keeping a safe margin between each train from signal light, to signal light.


Centralized Traffic Control…(CTC)

Centralized Traffic Control (CTC) is a term used to describe a system that allows remote control of a traffic control system. CTC allows a single dispatcher to directly control and monitor a long section of railroad instead of a track warrant being given, often a whole subdivision. CTC provides the greatest traffic capacity for a line, as the person with the traffic overview is also the person directly controlling the traffic. This happens with the dispatcher for each train.

Track torpedoIf an area of track has no ABS or CTC, it is presumed “Dark Territory”. This is a track torpedo I set out on the track, but, of course later removed above.  When a train rolls over the small pack,….POW!  Thus the train-crew knows there is another train in the area and take necessary precautions, since Dark Territory has no means of lighting signaling systems to warn other trains.

Signaling systemsThis is a track-detector.  If dragging equipment anywhere on a passing train comes in contact with this detector, the detector-flap will be activated thus sending a notice to the train-crew either by radio or by automatically giving the next lighting signal a red block thus the engineer will stop the train to investigate.  Also this detector has an infrared heat sensor, (the small gray box).  If any train wheel measures above a certain temperature, the detector again will be set off and appropriate action will be taken.

Train signalsThis here is an overhead detector.  This type detector takes measurements of each rail car as it passes and if there are any defects with the train the detector will send a signal to the train-crew via their radio or by giving the crew a red signal to stop their train and investigate.  The train-crew then will place the train into what’s called “emergency”.  The entire train will be walked alongside while the defect is located and either fixed there on the spot or if the defective rail car has to be taken to a siding or spur and set out.

Track detectorsThis here is a set of mainline overhead CTC signals.  Each train out on the mainline is given either green, yellow, flashing yellow, red or lunar.  Each signal means a certain task is required of the engineer.  Each railroad company has their own set of rules for what each lighting signal means thus keeping the flow of traffic safe at all times.

Rail traffic signalsThese type signals here are siding signals.  They signal the train-crew to either enter the siding or to maintain track-warrant speed on the mainline and not enter the siding.

Drarf signalsThis here is a dwarf signal.  They are used mostly in switching yard areas.  They let the engineer know which tracks are lined up for entering and exiting.  They also can be found at the stopping-point in a siding area that trains use to pass one another.

Swap-boxesThis is a swap-box.  This is the area where all the electrical wiring runs into one area where it then is directed to the appropriate signal that is to be given a command.

 This is an “AEI” detector.  “AEI” detectors read railcar information on each car that rolls by this white box.  This tells of its load contents and carrier as well as costomer.


About hoboshoestring

I'm a professional hobo of nearly 25 years. This blog is a collection of my most memorable freight train trips; most with photos. First things first, a hobo is someone who rides freight trains and is not a homeless bum on the city streets. I've been hopping freight trains for transportation since 1989. I've ridden over 340,000 miles of steel rails in 49 US states, eight provinces in Canada and 14 states in Mexico. I ride all rail lines in North America. I have hundreds of hobo trip photos that can be viewed by clicking my "Photostream" at: http://www.flickr.com/photos/30715417@N04/
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