Rairoad Signaling

[Anonymous]

I am new to these boards, but a long time train buff. I am looking for a book on Railroad Signaling. Could anyone suggest a good title and where to get it.[8D]

[Anonymous]

Different railroads often have different signal systems. The most accurate guide would be the current timetable of the RR 's that you are interested in. Signals change from time to time within a particular RR. For example, on the CP, a flashing yellow light was called 'Approach Medium'. A couple of months ago it was changed to 'Advanced Approach'. BNSF still calls it 'Approach Medium'. Signals differ wildly even on a particular line depending on the age of the signal and how it is wired. We still scratch our heads as to what the logic is behind some of the signals.

[ndbprr]

Lets start with the basics. Pretty much like a traffic light to start with. Green means keep going, yellow means approach the next signal prepared to stop and red means stop. That much is easy but signals are also used to indicate routes like at a switch. So you could see red over green or green over red depenent on the route the train will take. Then there are the railroad specific signals like a flashing yellow under a stop signal which on the PRR meant that a train could proceed until it was off the grade it was on at no more than 15 mph. I am a chemical engineer and find the rules regarding signals very difficult to understand or interpret so keep at it.

[Anonymous]

Thanks for the info. I am actually a truck driver myself. So in my line of work when it comes to signals, green, yellow and red are pretty much it. I realize that railroad signaling is far more complex and that apparently there is a lot of variances amongst the various railroads. In the last couple of years I spent most of my spare time learning about "Motive power". Before that it was freight equipment (different kinds of freight cars). I now want to tackle signaling as it has always intrigued me. When I was young, growing up in Appleton Wisconsin, I would watch the "C&NW 400 passenger trains come thru town. There was a semaphore near my home. After the train would go by, I would watch the arm and lights go thru it's three phases. By the time the arm was up, I knew that the train was well on it's way to Green Bay. Anywho, I,m going to keep looking for a book on this. Thank You for your responses and for future ones!!

[Anonymous]

Like everyone said it is the basics of stop, go, and prepare to stop. But some of the bigger roads, are replacing what used to be a bottom yellow board to a white boadr, because they claim they can see white better during fog, than they can see yellow. If the signal is on the bottom portion of the board, it usually means to proceed slowly, because there is a train in front of him between that board, and the next on down the line. The next signal is a High yellow on the top of a three light board, which means the next portion of the track is clear to the next signal, but may be white/yellow. The next one is usually a double yellow (yellow over yellow over red) and means that the train is clear thru the next two sections of trackage rights. If the board shows a high green it is clear to keep going, but watch the other boards.
Now the new signal set up is a little different. I have seen bottom white boards meaning the next portion is ocupied ahead. Then if you find a yellow over a green over a red, it is telling the engineer, that he is going to be crossed over to the track alongside of the one he is on and that it is clear ahead for at least 3 boards. If he has a yellow green over red over red, it means he is clear to run straight on the track he is on. They communicate with the dispatchers who tell them what they are going to do with them.
Ralph Zimmer (former tower operator from the IHBRR in Indiana).