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.
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.
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.
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.
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.
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.
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.