A Spotter's Guide to Traffic Signals | North Star Highways

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.)

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These were made from the s to the mid-s. 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 s, 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 4th 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 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 s 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 s 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.

Later Eagle Models

In Eagle was bought by a company called Mark IV Industries. Shortly before this Mark IV had also bought out Automatic Signal. Each company had 8&#; and 12&#; vehicle and pedestrian signals in poly and aluminum, so a total of 24 products, so simplification was inevitable.The following products survived the merger:

1. Eagle Alusig, 9&#; pedestrian only as type SA, later discontinued
2. Eagle DuraSig, 9&#; and 12&#; pedestrian and 8&#; and 12&#; vehicle as type SA
3. Automatic polycarbonate, 8&#; and 12&#; vehicle as type SIG, 8
4. Mark IV aluminum, 12&#; pedestrian and 8&#; and 12&#; vehicle as type SIG, 8&#; vehicle later discontinued.

&#;SIG&#; is known as &#;SG&#; with LEDs, and now can only be ordered that way. Of these types, SA continued to be used in the cities, while Mn/DOT and the suburbs switched to aluminum SIG exclusively, (referred to by enthusiasts as &#;Bubblebacks&#;). Mn/DOT finally switched to polycarbonate a few years ago, and suburban agencies followed, so now we&#;re starting to see type SA in the suburbs.

Siemens bought Mark IV&#;s signal products in , discontinued the Eagle name, and moved Eagle away from the Quad Cities to Texas. In Siemens sold Eagle&#;s signal head business to a company called Brown Traffic (while keeping the more profitable control business). Brown has indicated they plan to re-introduce the Eagle name, and update the molds to the new Eagle logo, which is a realistic perched eagle rather than the stylized &#;Thunderbird&#; of the past 50 years. The headquarters has returned to the Quad Cities, although manufacturing will likely stay in Texas.

Econolite (and GE) Products

Econolite is based out of California.  They&#;re most noted by enthusiasts for producing a line of neon pedestrian signals that were ubiquitous in California (now virtually all gone), as well as distinctive looking vehicle signals. They got into the vehicle signal business in the early s when General Electric, one of the early players, changed their design and sold them their old molds (In GE would exit the business entirely and sell them the remainder). I&#;ve seen s-early s Econolite products used here; there are some in St. Paul, but they tended to be used more in the suburbs.

GE, and later Econolite 8&#; signals were rather distinctive in that there were vertical grooves running down the back.  A late s production change was to shorten the grooves so they didn&#;t go all the way to the end of the section due to water ingress problems. Enthusiasts refer to these as &#;Groove Back&#;, &#;Long Groove&#; and Short Groove&#;. The corresponding 12&#; signals were circular and had a concentric design, &#;bullet backs&#;, and could come with either round or square doors. (Econolite models numbers were E31 for 8&#;, T31 or ST31 for 12&#;, and C35 or SC35 for a combination, the &#;S&#; denoted square doors rather than round) These designs lasted until the early s, when &#;Buttonback&#; 12&#; signals debuted. &#;Buttonbacks&#; lasted until the early s. These were the last Econolite products I&#;ve seen used here.

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McCain Signals

In the past decade or so McCain polycarbonate signals have been showing up. They&#;re very plain looking, but they do the job. 8&#; models are often used  as ramp meters. Except for a smaller size they are identical.

Programmable Visibility Signals

In their own category are &#;programmable visibility&#; (PV) signals for when it&#;s desired to only allow it to be seen from a narrow viewpoint, for instance two roads the meet at a sharp angle.

3M Model 131, introduced in , was the first of this design. Rather than a conventional traffic signal bulb (which resembles a standard clear incandescent), these used a compact, high intensity PAR lamps that was accessed from the back. The light from the bulb went through a frosted diffuser, and then a clear optical limiter lens, followed by the acrylic tinted Fresnel lens in the front. The whole assembly could also be tilted at different angles. How it worked is once the light was mounted, you&#;d go up in a bucket truck and peer through the optical limiter toward the road, seeing an inverted image of the road.  You&#;d then put a special 3M tape (more or less heavy duty duct tape) on the optical limiter to cover parts of the road you didn&#;t want to see the light.

Eventually McCain introduced their own PV signal to compete directly with 3M. They looked similar, except for the back (which is actually a re-purposed 8&#; section) and using standard circular visors. This area was never enthusiastic about them, preferring to support the local company. However competition and declining orders eventually led 3M to discontinue their model in so for a while McCain was the only PV option.

As a more modern  alternative, a company called Intelight offers &#;electronically programmable&#; signals. Basically rather than a few high powered LEDs as used in most signals, there are a large number of standard LEDs in a grid. These can be selectively disabled through software to restrict the visibility, generally done by a smartphone app by a worker in the street. These have large heatsinks on the back and so are hard to mistake for anything else.

This concludes the spotters guide. I&#;ve left out products by a number of companies that have only a minuscule share of the equipment here, but what I have have included amounts to well over 99% of the equipment in service in Minnesota