Kato Unitrack 3 color signal question

[mecgp7]

I picked up a Unitrack 3 color automatic signal and so far it is only a two color signal. It goes back and forth between red and green but, the yellow doesn't ever turn on. Did I get a bum signal or am I doing something wrong?
I run DC if it matters.

[mecgp7]

Did a little research and apparently the yellow comes on only of the loco is followed by cars that  have metal wheels. Haven't tried it yet.

[One of One-Sixty]

Beat me to it....

[mecgp7]

Well, I ran a train with cars that had metal wheels through the signal several times. The yellow light doesn't work. The switch from green to red now has a pause and I assume that is when the yellow light should be lit. Bummer.

[peteski]

I don't have these signals and I don't even have a manual for them but I do recall seeing them in action few years back, so I'm just thinking out loud here.

From what I remember when the passing train trips the signal from green to red, after it passes the trigger area the signal turns yellow for a certain amount of time. After that preset time perod passes, the signal turns green again.  So I think that the yellow is turned on by an electronic timer.

The other possibility (totally speculative on my part) is that multiple signals need to be daisy chained together. Assuming that this is even possible. Sort of like a real signaling system works.  Then the yellow signal will be turned on by the next signal going red.

Isn't there a manual available for these somewhere? 

[Mark5]

It was correctly posted that all cars in train should have metal wheels. It is designed for use with Kato equipment, which in all cases have metal wheels (AFAIK).

Mark

[One of One-Sixty]

Sounds like you got one with a faulty bulb, that long pause is when the yellow is suppose to be displayed.  The signals work with the sensor switch embedded in track.

Kato did at one point discontinue these similar to what they did with their automatic crossing systems, only to reintroduce them just a year or two ago.

Do you have the signal with the while or black signal mast?  If it is the black mast you have an older signal which might account for the bulb not functioning properly, if you have the white one definitely a manufacturer defect and I would try to get it exchanged for a different one.

I have both the older and newer ones and according to the back of the box.

1) Lead car (locomotive) passes over sensor, causing green light to change to red.
2) After 3 second delay (achieved only by rolling stock with metal wheels), red light changes to yellow.
3) Yellow light changes back to green after an additional 3 seconds.

*During reverse running the signal will remain red.  The signal will remain green when idle.

[mecgp7]

Thanks for all the feedback. It is an older unit. Really not a big deal as I purchased it as part of a bigger set. Honestly, I don't see why I would ever need functioning signals anyway. I am no rivet-counter and don't try to replicate prototype operations