I have the mast and dwarf type signals on my layout but use them only to indicate which route
is selected on a turnout. Neat to have them change colors as the turnout is thrown. Makes
things easier in the yard area visualizing train direction when there are multiple turnouts in the
same area.
It also falls into my grand scheme to have night time scenes on the layout.
The red signal shows the turnout is thrown against the diverging route on the right hand track. The green indicates
the straight through position is selected.
I use Caboose Industries ground throws with switch contacts to control the signals. Makes for an effortless method
to change aspect colors on the signals as the turnout is manipulated.
Wiring schematic for the signals. A red LED from one signal is wired to the green LED of another signal and are wired to one side
of the Caboose Industries ground throw. The green LED from the first signal is wired to the red LED of the second signal and
are wired to the other side of the ground throw. The center contact on the ground throw is wired to the negative side of a 12 volt
DC power supply. All of the LED anodes (positive side) are wired together to the positive side of the 12 volt power supply.
The above photo shows a similar wiring arrangement using dwarf signals where two tracks merge.
I am going to guess that they wont be much taller than perhaps an 1 1/2?? That being said - those Dwarf Sigs" will be appropriately named 
