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Wednesday, May 27, 2015

No Respect - The Safetran Unilens

While riding up the Caltrain Corridor I noticed a little something that once again reminded me that the Safetran Unilens signal, for all its seeming usefulness, is the ugly duckling of the signal world.  The Unilens series (now in its second generation) was created as a solid state replacement for the old fashioned electro-mecnahical searchlight signal.  Inside, instead of a moving colored filter, one will find four lamps each connected to a single (hence the name) lens via fiber optic cables. This seems like the perfect solution to the old problem of getting multiple colors out of a compact signal head, and in fact should have been a marked improvement seeing as each Unilens head could support 4 colors instead of three.

From the Greek, Uni meaning one and lens meaning lens.
 Not only could the Unilens play the role of a dwarf signal, it could also be used in mast mounts behind a circular target just like the older searchlight and in the case of close quarters transit applications the Unilens had an additional trick up its sleeve with a goose-neck attachment that allowed the lens  to be placed a foot or two away from the actual lamp housing.

Initially adoption was good with a number of traditional searchlit railroads, such as the Delaware and Hudson and Canadian Pacific, buying them as a simple replacement for the US&S H series and GRS SA's they had been buying for decades. The BART rapid transit system enthusiastically bought into the whole goose-neck configuration for its limited number of wayside signals

But then things took a turn for the worse.  Crews complained that the small internal lamps didn't provide a bright enough light and the lamps themselves were proprietary, expensive and prone to burning out.

You be the judge!
The Canadian roads that briefly used the Unilens in high signal applications switched over to Darth Vader style LED lamps, and the transportation authority that owns the Coaster route to San Diego actually took the step of replacing its high mounted Unilens signals with target configuration Safetran colorlights.

I am posting this because while passing by the BART Millbrae station I observed that the goose-neck Unilens signals, perhaps some of the only examples ever purchased for rapid transit, had been swapped out for bland and boring LED traffic light type signals.  No the Unilens isn't going the way of the position or searchlight signal.  CSX, SEPTA and BNSF still prefer them in close clearance signaling locations across their systems, but as a replacement for what was once the most common signal type in North America if not the world, the Safetran Unilens has fallen dismally short.


  1. The issue was also that the fiber eventually got hot and the ends melted causing the fiber to yellow and caused the indications to get a yellow hue. BNSF still to this day is installing new safetran unilens signals up north. The second generation also had plastic reflectors that the gloss coating would over time just disappear causing less light to shine though, the generation one signals had special lamps and since, the lamps are almost impossible to find.

    1. Thank you so much for the information. I knew there was something wrong with them, just wasn't sure of the exact details. Shame that they turned out to be so cheesy. It was a great concept.

  2. The current Unilens uses the same bulb as a standard incandescent signal and does not require a special bulb.