Painted Ladies - North American Signal Paint Schemes

In the age of steel and iron, paint was primarily used to protect the metal from corrosion, however in the world of railway signaling other factors, both aesthetic and practical, played a role. What follows is a brief summary of signal paint schemes over the years.

The simplest is the all black scheme that puts literal emphasis on the signal lamps themselves.  Cheap and available, black paint over the entire signal structure (as opposed to just the signal heads) was popular with northeastern roads like the Pennsylvania and New York Central for use on mast and dwarf signals. Today, all black signal paint schemes are primarily used by PRR-successors Amtrak and the Long Island Rail Road.

Although slightly more complex, the silver scheme was just as popular as all black.  Generally seen on mast signals out west and some signal bridges and cantilevers in the east, a silver paint scheme would reflect sunlight and prevent the signal structure from heating up (an issue that is salient out west and on riveted signal structures).  Of course the backing around the signal lamps remained painted black. 

Championed by Conrail and earlier iterations of CSX, the two tone black and silver paint scheme represented the apex of signal paint design. This scheme keeps the all black paint anywhere in the general eye line of the signal heads, but paints the lower part of the mast silver so that it stands out perhaps in case of power failure. This scheme was used on some CSX and NS controlled lines up through the 90's, however Conrail was its biggest proponent.  Conrail not only applied the black backing paint on otherwise unpainted aluminum structures, but maintained the practice under the auspices of Conrail Shared Assets up until the present day.

 I suspect the primary reason this type of paint scheme was abandoned was because the paint tends to flake off aluminum structures after a decade or two.

The switch to corrosion free aluminum signal structures largely eliminated the need for painted signal equipment.  Aluminum signal heads and targets still needed to be colored black for visibility reasons and turned to factory applied anodized coatings.  This new black-on-unpainted scheme has largely become the standard, however BNSF has broke from the back with silver backed signal heads instead of black.  This has seen intermittent use on Union Pacific and some other small railroads. 

 

Finally we have the odd duck of the lot in the form of the Western Pacific railroad that painted its signal structures a pleasing mint green.  At a quick glance the paint may appear silver or gray, closer inspection reveals it to be a very light green.  This unique color scheme faded with the demise of the WP and it is not clear if there are any remaining mint painted WP signals in service.

That's all of the paint schemes I can think up at the moment.  Please let me know if the comments if I missed any.