Green over Green on the B&M

The current issue of Trains has a story on the upgrading of the Fitchburg line which mentions the existence of some surviving searchlight signals displaying G/G for Clear. I know that the B&A used G/G in the Boston area and NYC on the lines leading to GCT where the signal spacing was so close that the usual sequence -- Y/Y = Advance Approach = proceed approaching second signal prepared to stop; Y/R = Approach = proceed approaching next signal prepared to stop; R/R = Stop and proceed -- still did not provide enough braking distance for the prevailing speeds. Accordingly, they introduced an additional aspect -- G/Y = Advance Approach Medium = proceed approaching second signal at Medium Speed (30 mph), with Y/Y on the next signal and so forth. Using the normal G/R for Clear would have meant that a train having passed a succession of G/R could then encounter a G/Y, and the signal department felt that it was counterintuitive and against logic for G/Y to be LESS favorable than G/R and therefore introduced G/G to display Clear (Rule 281, same as G/R) in territory where G/Y was also used. The sequence in approaching a Stop signal would then be G/G, G/Y, Y/Y, Y/R, R/R, which made a logical progression.

My question is: Did the B&M also use G/Y for Advance Approach Medium or something similar, or was G/G the equivalent of the night aspect of the traditional 2-arm 3-aspect lower-quadrant semaphores, then still in wide use, on which G/G = Clear, G/Y = Approach, and R/Y = Stop and Proceed?

On the Fitchburg Line between Boston and Waltham the searchlight block signals were all two-headed (3 heads for the interlocking signals). They could display G/G, Y/G, Y/R, R/R. On the B & M I think Y/Y was advance approach. I never saw it displayed on the Fitchburg (I got my share of cab rides, back in the days when you could..I worked in the General Office), however, I rode a Boston-North Conway "Last Snow Train" (it wasn't) and coming back to Boston on the Wildcat we got a Y/Y on the approach signal to Wilmington. That's the only time I ever saw a Y/Y on the B & M. The signals between Waltham and Boston may have been set up to display that indication but I never saw it. The two headed signals between Waltham and Boston were staggered heads if it was an approach signal(next signal was an interlocking) one over the other if just a block signal. The Boston-Fitchburg searchlights were installed about 1930 during a massive upgrading that saw stone ballast installed and 130# and some 131# rail (with Neafie joints).

I probably have a few B & M rulebooks, 1948, 1961 or the one from 1930s for reasonable prices. Signal aspects in the '48 and '61 anyway have color, not letters on the sample signals. Contact me thru railroad.net if you are interested.

Oops. Y/Y is approach slow, not what I said in my previous post. Eastbound on the Fitchburg the automatic block signals with two heads began around MP13 near the former Stony Brook Station at the Weston-Waltham Line.

I've never seen an approach slow (Y/Y) on automatic signals before on the B&M, but they could have existed. The ones you do see now are G/R and G/G for Clear, Y/G for Approach Medium, Flashing Y/R for Advanced Approach, Y/R for approach, R/R for Stop and Proceed (and now just proceed as restricting).

That's what I was wondering about -- what the distinction was between G/R and G/G if they used both. On the NYC they both appeared as figures in Rule 281, meaning Clear, with no explanation in the rulebook itself as to when one was used and when the other, and both represented the same indication.

I don't know B&M's logic for g/g for a clear, when most others used g/r. I sometimes run the Fitchburg from XO to Eagle Bridge. I haven't been out there in a while. I recall heading west and getting a double green approaching CPF 464, and lined for #1 track. I went a later time and got a conventional g/r. Am I remembering incorrectly, or was it changed?

I've seen G/G at MP 449.5e within the last month, so it still exists on some part of the West End. When you run up to the Batten Kill, is the switch dispatcher controlled? I think the main is set up for the #2 track, and when lined the 449.5e signal will read G/G. I don't know what the trackage looks like where the BK comes into Pan Am, but I would imagine you guys would probably only ever get an approach there?

The BK is a power switch within CPF 448. A restricting indication appears when lined for the BK. The staggered signal approaching 448 is approach for us, but I can ask some B&M friends if I think of it.

I'm the author of the Trains Magazine article. Thanks for the info about the NYC's signaling -- fascinating stuff.

As for Y/Y on the Fitchburg, I've seen it on the westbound distant signal to SOUTH ACTON. I rode the Fitchburg Line twice for the story and it displayed Y/Y both times, for different home signal indications. The first was on a Fitchburg train and the home signal was R/G/R Medium Clear and the second was on a South Acton turn, home signal R/R/*Y* (flashing yellow), Slow Approach. The MARTIN STREET hold signal just beyond the platform was of course at Stop.

I'm not sure why we got a Y/Y distant for a Medium Clear.

Elsewhere on the Fitchburg we received a similar Approach Slow at CPF FG on a triple-head interlocking signal, Y/Y/R.

Oh, and for any other signal aficionados, you may enjoy this photo of the westbound approach to CPF Slab City in Shirley, MA. It's a staggered-head G/G Clear with both a grade marker and a distant signal marker attached. You don't see that every day!
http://i233.photobucket.com/albums/ee26 ... G_3257.jpg

In a first for me, the 380-2 stagger block at Patterson Rd., Shirley, was G/G on 12-26-2013 at 0725. For the thousand-plus times I've driven by it (it was my commute route for 7 years) Approach or Stop was the indication.

Sometimes Approach Slow is used in advance of a medium signal, if the next block is short. In that case you would already be at least at medium speed. An example would be Approach Slow, next signal Medium Approach. If the block which the MA signal was short, you would already have ahold of hour train.

This is used in the D&H in a few places. Crescent is one. If you are lined up the Freight Main at CPF 480, you get Approach Slow if 478 is lined, but 477 is not. This is because 478-477 is a really short block. I'm sure B&M used the same logic.

Hi
Maybe this will answer your question about G/G on the B&M , the information was taken from the book Vanishing Markers , by Ralph E. Fisher. Memories of the Boston & Maine 1946 to 1952 . Mr. Fisher worked as a Brakeman for the railroad .

Thanks for the post. On the searchlight example, I can't make out whether there is any explanation of when G/G is used vs. G, unless it's a holdover from semaphore days, to duplicate the night aspect of the semaphores. (If there's a way to blow up the page on the screen, I can't get it to work.)

Hi
Is this better , Pat