I’m in the middle of some scenicking and am ready to plant some signals. The layout is generic midwest, ATSF & IC, in the 1950s timeframe. The signals are dummies, painted and weathered.
I’m reasonably certain about where most of them would look right and be somewhat realistic. The ones that I’m not certain of are the “dwarfs”. As a friend indicated, they likely belong in yards where they won’t block views. That makes sense, but I was wondering if they would go anywhere else?
I’ve seen them in passenger stations, in tight clearance areas when a full mast won’t fit, and for a secondary or industrial line accessing a main track. Some of the former Pennsy trackage around the Harrisburg PA station was loaded with dwarf signals.
The CGW, and I suppose other roads as well, sometimes used dwarfs on passing sidings. It was cheaper to install and maintain and also helped eliminate confusion as to what each signal was controling.
Dwarf signal usually were located where there was not enough clearance between two tracks - like double track or a passing siding. They sometimes were used to control a siding that entered the mainline via a spring switch as well. The key item is that they were generally used within interlocking limits and were a ‘Stop & Stay’ type of absolute signal. I have seen them used a a ‘push’ signal in a yard or some special use not related to actual track circuits.
There are multiple names for these signals depending on the railroad or region. On the Burlington, they were referred as ‘Pot’ signals. On the Milwaukee Road, they were known as ‘Dummy’ or ‘Bug’ signals, depending on what part of the railroad you were at.
First is the HOME signal, controlled by the tower protecting interlockings. This is an absolute signal. It will have no number plate on it, or the number plate may simply be an “X”. Any number that may be associated with it would indicate the number of the switch lever that controls the signal. It is frequently seen with a block signal over a home signal.
The Second one is the BLOCK SIGNAL, this is an automatic signal, and can be located anywhere along the line. It informs on the presence of a train in the blocks ahead of it. It does have a number plate on it, and the number is the MILE or CHAIN number of the signal. The number plate itself is part of the signal aspect, so you might read it as red over number plate if you like, this is not an absolute signal, but rather stop and proceed at restricted speed prepaired to stop within 1/2 the distance to the train or other obstruction ahead of you. If there were opposing traffic on the line ahead of you, you would have had an absolute red at the home signal protecting this track.
An TRAIN ORDER signal is at a manned station house where written orders may be passed up to a train. A Red signal would command a full stop for orders, an amber signal would allow collecting the orders on the fly and a green signal would indicate “No Orders”.
Dwarf Signals (with no disrespect to vertically challenged persons) could be any of the above, but most likely would be HOME signals controlled by the opperator withinin an interlocking plant. The home signal to enter the plant would be on a mast or a bridge, but within the plant positions of individual switch points might be indicated by a dwarf. Of course as said, they could appear anywhere, since a signal is a signal, but there would have to be a reason for teir use, since they would not be seen from afar. So let us say that they mostly tell of the position of a single set of switch points.
One other point regarding location of dwarf signals. They were generally only used where the speed of an approaching train was slow. As already noted, that is typically urban terminals, exit from passing sidings, and the like. At a diamond crossing with two track directional running, there might be dwarf instead of a mast for the wrong main direction.
Out on the mainline, if there was not enough clearance for a high mast, a bridge or cantilever structure would be used to keep the signal high.