Height of Green Line Catenary vs. Height of Commuter Rail

My pleasure.

Original Riverside (D) line catenary height: 16 feet out in the open, 14-1/2 feet minimum under bridges.
(Riverside Line Extension, by Edward Dana, published in 1961 by NRHS Connecticut Valley Chapter in Transportation Bulletin no. 65, page 12.)

From the appearance of the trolley poles I would have guessed the height of the catenary back then at 17 to 18 feet for street running sections. The 13-1/2 feet seemed right for the subway.

Are you sure the 13'-6" sign is for the catenary as opposed to for all overhead objects including the yellow Trolley Stop sign in the picture?

You'll need a more scientific measure of the catenary height as seen outside the window. For example sight along a carpenter's level and then drop a plumb line out the window down to the sidewalk.

This part seems strange to me. Judging from the remains of old ears and hangers, the catenary in the Green Line subway is in may places lower now than it was back in 1961 or so.

What is a flangeless frog?

It's a swamp frog that can't ride on trains.
No - "flangeless frog" is my terminology. I'm sure that there's a technical term for them like "flangeless frog" but I don't know what it is. But anyway it's a "frog" (crossover section of a turnout shaped like a diamond) without a flangeway either cut into the rail or rail spacing to clear the flange of the car's wheel. The flange of the wheel rides up on what would be a flangeway near to the top of the uncut rail that it is crossing, rides over the rail, and then just as smoothly, ramps down on the other side. The wheel is actually up on it's flange at the point that it's crossing the adjacent rail. There would be a sturdy restraining rail on the opposite running rail, keeping the axle from sliding laterally. I understand that a Class 1 railroad used them on some of their lines with Pullman sleepers - called them "silent crossings", I believe. I forget the RR. I know that the old Orange Line (Main Line) had one just outside Forest Hills terminal on the El. It was at a partially removed turnout at the beginning of the old abandoned ramp which lead down into the yard at the Arborway at one time that the elevated trains once used. There was a slight groove worn in the crossed rail caused by useage, but no flangeway. I believe that I've seen them on the trolley tracks as well, mostly in yards, etc, but can't remember where. They're used at locations which get little traffic on what would be a full turnout. This way, they don't have to maintain a complete turnout and it's easier on the wheels which use the more often used segment of the turnout and don't have to drop down into the pocket at the frog.

Would that "flangeless frog" be like what we have at a couple locations at STM (Doherty Switch/north end of Riverside and Highwood lead switch off of Butler Grove lead), of have those just had sections of the frog filled in? (probably way off topic at this point...sorry)

Sorry, I honestly don't know, not being familiar with the Seashore locations that you are referring to. I don't want to hijack Guilford Guys catenary thread, so if there are any more discussions about unusual rail, why don't we go here:
http://www.railroad.net/forums/viewtopi ... 36&t=47529

MBTA3247 wrote:What is a flangeless frog?

While doing a post about the Main Line tonight, I happened to run accross one of my old photos of a switch with a "flangeless frog" on the Main (Orange) Line just outside of the old Forest Hills Station. If you look closely, you'll see that the "frog" does not have a flangeway for all practical purposes on both inbound and outbound side's diverging rails.The linear rail heads actually did have a small indentation as a result of a few cars running over them over the years, but in fact were installed with un-cut rail. Notice the rampway for the flange on the diverging rails.


http://naphotos.nerail.org/showpic/?200 ... y&BOOL=ANY

Is there a source for the dimensions of the poles used to support the Green Line power lines on Huntington Avenue near the NDA?

nearboston wrote:Is there a source for the dimensions of the poles used to support the Green Line power lines on Huntington Avenue near the NDA?

I bet if you had an Android phone you could stand at ground level and get an app that does fairly precise measurements through the phone camera.

Poles across the system have wildly varying ages, and whatever default poles they stocked at a given time could have different height or thickness from the default poles they stocked at a different time. Measurement's only going to hold consistent for the poles or sequences of poles that are similar lineage. Wire height has been kept at more or less consistent spec out in the open ever since pantograph catenary first got strung, but what size pole the wire's hung from can be a crapshoot.