Hello All, I am looking at a photo on page 187 of Michael Kelly's Rails Around Missouri that has generated a question about Frisco's signal installation practices. The photo shows a train passing one end of the siding at Newberg on the mainline. The odd thing I see in the photo is that both the signal next to the mainline and the signal next to the siding are short signals. Looking closely above the train, you can see the signal on the far end of the siding switch is a tall signal. The expectation I have from other signal installation photos is that the signal next to the mainline on the siding end of the switch will be a tall single headed signal, but otherwise it looks like the installation in the photo in the book. Now, the question: how common was this dual short signal installation on the Frisco, and what factors dictated it's use? I'm asking because I am building modules that include the end of a passing siding with a signal installation, and it certainly is easier to protect a short signal than a tall one, but I haven't noticed that arrangement before. Paul P.S. I purposely did not use the term Dwarf Signal in the description above because track charts describe the signals at the ends of sidings as A signals and the intermediate signals as Dwarf Signals, so at least on Frisco track charts Dwarf signals are not necessarily short signals.
In short, clearance and speed factors. When the Frisco installed the signals, the railroad almost always placed the signal on the engineer's side of the track. In this location, the yard track is entering the main, speed at this spot for both the main line and yard track is slow, and it was cheaper to install a pot/dwarf signal than is was to move the track to allow a tall signal. the Frisco would also vary the height of masted signals to allow better sight lines in undulating territory. It's been only during "recent" times that the adherence to the "right-side" rule has not been enforced rigorously.
Thanks Karl. I know I've seen short (4' or so) masts at other locations on the signal next to the siding, which was much more typically a dwarf signal than the one next to the main. So, basically, I can justify shorter masts just about anywhere, as long as I'm not modelling a real location . I'm somewhat curious as to the use of the term "dwarf" signal on the track charts. I know that not all of the intermediate signals were short. I know the "A signal" refers to an "Absolute Signal", but that is defined in the rule book as a signal with an "A" plate or an "A" painted on the mast. ( http://www.frisco.org/shipit/index....erations-of-trains-by-ctc-august-1-1943.6139/ ) Paul
I have never been able to determine why the modern track charts used that taxonomy, i.e., dwarf signal in lieu intermediate signal. There are numerous examples where the Frisco placed dwarf/pots/ground signals on short masts or atop instrument cases to improve sight lines.
Here is the cover photo from Modern Railroads. Note the pot/dwarf signal that controls northbound movements on the West Main. This is at Rosedale.
In that particular case of the photo, the bridge cannot be moved, providing a minium clearance for a person riding the side of a car. If the track centers could be wider then a tall mast could be used. Fixed structures often call for changes. Bill.
