MBTA's track signals... How do you read em?

I know this is the most basic railroading question. But I've searched online and I can't find any sites that describe in detail what all the lights mean.

As far as I can tell, each signal has 6 lights, three per track. And as far as I can tell, the top light tell you to Stop, Go, or Go Slow (red, green, yellow). For the life of me I can't figure out what all the other lights mean.

I've also noticed they seem to be removing overtrack signals in favor of 'next to track' signals. Why is this?

http://photos.nerail.org/showpic/?photo ... 103%3AMBTA

Wow it took me a long time to find that. I guess railfans don't like signals in their photos?

Here's a place to start with NORAC signal indications:

http://vnerr.com/training/NORAC_Signal_Rules.htm


As you can tell from the charts, there are many, many different ways of displaying various signal indications, as this varies by railroad. Just look for the types of signals you see along the MBTA lines you're familiar with.

This site will allow you to see how the signal indications relate to specific conditions on a simple track diagram:


http://raildata.railfan.net/java/DivRte/NORAC.htm

As you can see, a signal will have different numbers of heads (which can contain different numbers of lights) based on where it is located and what indications it has to display.

I remember as a kid seeing double green signals on the intermediates. Has that aspect disappeared? Of course, this would have been long before the T existed, still the B&M.

As mentioned above these are signals used by numerous railroads that operate under NORAC (Northeast Operating Rules Advisory Committee) Operating Rules, they are not the MBTA's own signals.

As for a double green, the only one you may see in this area now would be on a dwarf. A double green on a dwarf is a "Clear Signal" where-as a dwarf with only one green or a red and a green would be a "Slow Clear" unless the red was flashing, then it would be a "Medium Clear". More on that can be learned by reviewing the NORAC Signals.

l008com wrote:As far as I can tell, the top light tell you to Stop, Go, or Go Slow (red, green, yellow).

Not true, there are many signals in which the top light is red, ie.: Medium Clear, Medium Approach, Slow Approach, etc.

It's still common to see double green on some distant signals to interlockings in places where the old systems have yet to be upgraded. This is true only on B&M trackage both Guilford and MBCR!

Here is a shot I took when I was with Guilford, this is the distant to Soap Stone interlocking in Zoar, MA.

http://photos.nerail.org/photos/2001103115350120712.jpg

Sorry, John, I stand corrected. I am more of a South Side guy, especially working for CSX, LOL.

Are MBCR and Amtrak still operating under NORAC, or do they have their own rulebooks as CSXT does?

MBCR and Amtrak both still use NORAC. Guilford does as well.

jwhite07 wrote:MBCR and Amtrak both still use NORAC. Guilford does as well.

Except when operating on CSXT property such as Back Bay to Worcester, The Framingham Secondary (Football trains), and the Grand Jct Running Track.

Some railroads used to use a double-green as their clear signal. That was the standard practice on the old New York Central Railroad. Those signals were still in use on the Park Ave. viaduct into Grand Central Station until the mid-1990's.

Correct. And when I was in college in Poughkeepsie, NY in the 60's, double greens were up there too.

The Fitchburg route still has double green, for example the first signal westbound leaving Belmont