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Prototype Block Signals

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  • Member since
    October 2012
  • 527 posts
Prototype Block Signals
Posted by eastcoast on Tuesday, May 9, 2006 9:04 PM
Hey There.
Can anybody please lead me to an answer to this?
I need to find out how far apart block signals are placed on a
railroad. This will lead to my next question.
How long ( distance ) is a block on the RR? My guess was 3 miles?
Need to know for sure.
On the signal itself, if color is yellow, does this imply that the NEXT
block is occupied ?
Please recommend a publishing or web where I can find more info!!!
Thanks much [:)]
Ken_ ECR [:)]

As I read MR, I did notice a book of signals, may order it.
  • Member since
    September 2002
  • From: Saginaw River
  • 948 posts
Posted by jsoderq on Wednesday, May 10, 2006 7:34 AM
There is no set length to a block. Some are so short you can see the next signal, some are miles long. Every rr had their own system and the lights mean different things on different roads. You need to be railroad specific.
  • Member since
    February 2002
  • From: Mpls/St.Paul
  • 13,807 posts
Posted by wjstix on Wednesday, May 10, 2006 10:26 AM
Generally - unless otherwise covered by the railroad's rulebook because of some specific, unusual situation - block signal indications would be:

Green: The next block, and the following block, are both clear.
Yellow: The next block is clear, but the following block is occupied.
Red: The next block is occupied.

By "next block" I mean the block protected by that signal, so if you were on a moving train approaching a signal, if it is yellow, it means you should continue on, but at a reduced speed, because the block you're entering is unoccupied, but the block after that is occupied, so you may need to stop at the next signal.

Stix
  • Member since
    February 2005
  • From: Southwest US
  • 12,914 posts
Posted by tomikawaTT on Wednesday, May 10, 2006 10:53 AM
On rapid transit lines and in very congested areas blocks can be very short, even shorter than one-train length. In such places, the signal head may well have more than the usual three bulbs or positions, in order to display the conditions for more than the next three blocks.

On the JNR Chuo-sen approaching Shinjuku (a major junction station in Tokyo) the block signal heads had five bulbs, and any reasonably strong boy could have stood next to one and hit the next one with a thrown rock.

Chuck
  • Member since
    January 2001
  • From: Guelph, Ont.
  • 1,476 posts
Posted by BR60103 on Wednesday, May 10, 2006 10:51 PM
Block distances were usually dependant on braking distance: a train should be able to stop from track speed between the yellow signal and the red one. Where signals were closer together for denser traffic, they would have extra signal indications like double yellow to allow the engineer to slow the train down.
The Toronto subway has blocks about a train length (500 feet) and keeps 2 red signals and a yellow behind a train.

--David

  • Member since
    April 2003
  • 305,205 posts
Posted by Anonymous on Friday, May 12, 2006 4:32 PM
QUOTE: Originally posted by BR60103

Block distances were usually dependant on braking distance: a train should be able to stop from track speed between the yellow signal and the red one. Where signals were closer together for denser traffic, they would have extra signal indications like double yellow to allow the engineer to slow the train down.
The Toronto subway has blocks about a train length (500 feet) and keeps 2 red signals and a yellow behind a train.
  • Member since
    December 2001
  • 1,179 posts
Posted by mvlandsw on Saturday, May 20, 2006 5:00 PM
I have seen blocks on the B&O as short as 1/4 mile and as long as 10 miles. The short ones use more than one approach signal to allow for stopping distance.
  • Member since
    September 2003
  • From: sherman,tx
  • 492 posts
Posted by tjsmrinfo on Wednesday, May 24, 2006 7:45 PM
here is a website on north american railroadsignals

http://www.lundsten.dk/us_signaling/index.html


tom
  • Member since
    April 2004
  • From: North Idaho
  • 1,311 posts
Posted by jimrice4449 on Saturday, May 27, 2006 12:26 AM
Many RRs an extra signal indication, approach medium, where the signal displayed a flashing yellow. The indication meant that the next signal was yellow and should be approached at medium speed.

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