B&O Color Position Light Signal Drawings 


O Scale Part 1  Part 2

S Scale Part 1 Part 2

HO Scale Part 1  Part 2

N Scale Part 1  Part 2

Instructions and Information by:

Michael Watnoski
October 7, 2007
(c) 2007 Posted here with the permission of the author.

This is the instruction sheet for using files CPL1_xx.pdf and CPL2_xx.pdf to create mock-ups for B&O CPL signals. The suffix on the files is the model scale. These were scaled for printing as many do not have the capability for scaling precisely. These files require Adobe Acrobat for viewing or printing. The mock-ups are intended as an aid for determining the configuration and placement of prototype size signals. The 'lamps' in the heads and markers can be darkened with a Sharpie type marker if a fixed aspect is desired.

CPL1 is a sheet containing front and side views of CPL ground signals.  CPL2 contains the components to build the mock-ups. Do a print preview to verify the paper size. In HO, CPL1 is a legal size sheet and CPL2 is a letter size sheet. Both will print on letter size in N scale. The CPL1 drawing will print on 3 legal sized sheets in O scale. The CPL2 drawing requires 2 legal size sheets.

The signals on CPL1 are drawn fully loaded, with the most common mast lengths, though all components are rarely used. This is used to position the parts in the correct orientation. This should be printed on an ink jet printer at 100% scaling. Turn off the automatic scaling option.  Check the dimensions on the corner with a scale ruler to verify the scaling.

Cut each set of drawings and mount on a sheet of Homosote or soft wood. Cover this with a sheet of waxed paper to protect it from glue. This will be used as an assembly fixture while assembling the components. Pins can be used to hold the parts while the glue dries.

Select a straight piece of bamboo skewer or dowel longer than the mast required, allowing for extra for mounting into the layout. The top end should be shaped to approximate the pinnacle. A pencil sharpener can be used for the tall pinnacle version. Paint the mast silver or silver with black above the lower marker position, depending on prototype you are modeling. Early steam era signals were painted completely black.

Print the CPL2 file on letter size cardstock. Again, make sure the automatic scaling is disabled to print at 100% or the scale desired. Overspray the printout with dullcoat to protect and seal the ink. Paint the back of the sheet with flat black. Cut out the parts required for signal.

The number boards can be lettered with a pencil or 6 inch number board decals. Sizes are supplied for 2, 3 or 4 numerals. The numbers are usually the signal location by mile marker position in tenths of a mile, without the decimal point. Multiple signals at the same location will have the last digit changed. Signals in the East bound direction will end in even numbers and West bound signals will have odd numbers. Number boards are only used on intermediate or permissive signals.

The 'P' sign is only used on intermediate or permissive signals on the up hill grade to allow heavy or 'Tonnage' trains to pass the signal without stopping, at restricted speed.

The yellow triangle is used to upgrade a medium speed indication to a limited speed. This was a carry over from semaphore signals and was rarely used. This is done now with flashing aspects.

The cantilever bracket with 'doll post' is used to indicate that there is a track intervening between the signal and track it controls. This is often used with a dwarf signal mounted on the base of the ground signal, or nearby.

The signal parts should be spaced off the mast a scale 18-20 inches, about 3/16" in HO. These supports should be painted black. No attempt is made to supply platforms, ladders, bases or foundations, as these are for mock-ups 

Note that these parts are drawn at the actual scale size. Most model signal parts are oversized and will look disproportionate if used build signals with the spacing shown.