A Spotter’s Guide to Traffic Signals, Part 1

Ever look at a traffic signal and wonder how old it is or who make them?  What follows is a two part “spotter’s guide” to the traffic signals of Minnesota. There is a certain slang used by people that are used by enthusiasts and collectors of traffic signals. I’ve included it here since it’s useful to describe and distinguish various models, in all cases it’s enclosed in parenthesis to make it clear that it is not official terminology. Now onto the guide:

Eaglelux KB63 “Tall Fin” and “Short Fin”

The Eagle Signal company is one of of the oldest of the signal companies, located in the Quad Cities for many years. And the oldest signals still in place in Minneapolis are the Eagleluxes, which was the original Eagle trade name for their signals. (This area has long shown a strong preference for their equipment).  Although a lot have been discarded in the recent traffic signal timing project, there still are some left, many with incandescent yellow. The most distinguishing feature of them is the art-deco like fins on the top and bottom plate. (Early sectional signals had open tops and bottom to each segment, there’s be an end plate on each end and tie rods holding the entire thing together.)

These were made from the 1930s to the mid-1950s. Early KB63s, the “Tall Fin” have a brass ID tag (normally covered by years of paint) on the bottom plate and no logo on the backs. Later there were running production changes where the fins were noticeably shortened, the Eagle logo was added to the back, and the ID plate was removed, and the fins were noticeably shortened The reason for this is speculated to be that the long fins interfered with more modern mounting hardware that was coming into use. This  configuration is known to enthusiasts as the “Short Fin”.

 

Eagle  “Rodded Flatback”

In the mid 1950s, Eagle dropped the Eaglelux name and introduced the “Rodded Flatback”. This was somewhat of a transition that was only in production for a few years. It introduced the simplified body style that would last for many years, but maintained the use of top and bottom plates, (now with no fins) with tie rods and the older style “slam latch” reflectors, and old small logo.  I don’t know of any that are in the field, but list it as there might be, and since it is interesting as a transition to the more modern style. Also of note this is the first that had dedicated 9” square pedestrian housings. Before if you wanted pedestrian indications you added a 4^th sections to the vehicle section and installed a black and white circular “Walk” lens, or later on a separate 2-light signal with an orange “Wait” and white “Walk”.

Eagle KB170 / KB380 “Flatback”

In 1960 Eagle introduced this model,   Gone are the tie rods and plates, all sections now have tops and bottoms and are held in place by internal clamps, and the reflector was a modern “H” shape.  The small Eagle logo was replaced with a much larger version. The initial production had a large trapezoid above and below the eagle, enthusiasts call these these “Trapezoid Flatbacks” and only they only lasted a few years before the trapezoids were removed (the reason for them is not known).

Although the 8″ variety are most common, in the 1950s 12” indications were introduced and promoted by the signal companies as being more visible on the newer higher speed roads and more complicated intersections. Initially only the reds were 12”, and only on overhead mountings (which became increasingly common during that time)- 8” and 12” sections have always been able to fit together. Later all three sections were 12” (and now 8” are only allowed on lower speed roads). Eagle’s version was designated model KB380 and besides the obvious size difference looks similar to the 8”. Some KB380s are found on older installations in Minneapolis and the suburbs, but they are not overly common.

Eagle AluSig and DuraSig

In the early 1970s there was a radical redesign. With catchy trade names came a move to internal hinges, and thumbscrews instead of latches to hold the doors closed. AluSig was made of traditional aluminum, and DuraSig introduced a new material- polycarbonate. Minneapolis and St. Paul were quick to adopt polycarbonate, the other agencies and Mn/DOT were very slow to and only recently have switched. The early DuraSigs had an unfortunate design in that the reflector was attached to the door, which made it difficult to change the reflector or lens, as well as visors attached with fragile tabs instead of screw. They were later revised to a more conventional design. DuraSigs worked well up here where they were immune from salt spray, but tended to bake and become brittle in warmer climates.

Both 8” and 12” DuraSigs were wildly popular in the cities, and the 12” versions are still being installed. AluSigs were more popular with Mn/DOT and the suburbs, even then they were mainly using 12”, so 8” AluSigs are uncommon, and when found are normally a pedestrian signal or the yellow and green of a larger assembly.

This concludes part 1. Part 2 continues with later Eagle models and other companies.