Western Railroad Discussion > Ex-MILW 4 Light Signals

Had my first look (as a passenger) at the ex Milwaukee line between St Paul and Chicago, and I noticed that the majority of the signal heads were a 4-light design which I've never seen before. Is the bottom light lunar white? Does anyone here have some information on this system? Any info would be appreciated. Thanks.

The exact arrangement/order of lights depends on the aspects to be displayed. For example, a distant signal to a crossover often has four lights configured Y-R-G-Y and displays green for Clear, a single yellow for Approach, red for Stop (or Restricting if it has a number plate) and yellow-over-yellow for Approach Diverging. At a crossover, the signal may be configured R-L-G-Y and show green for Clear, yellow for Approach, lunar or red-over-lunar for Restricting, red-over-green for Diverging Clear, and red-over-yellow for Diverging Approach. When needed, some of these signals have five lamps (e.g. Y-R-L-G-Y); standard automatic block signals have three.

I find these CP signals very interesting since some aspects require more than one lamp to be lit on the same signal head/arm, which is not common on high signals in the U.S.

Dave Malohn

The four-light signals went in after the Soo took over the Milwaukee and single tracked it. I was always wondering what the extra light was for. But since I moved to the east coast, I don't see much of anything outside of New England.

Thanks for the info. They are unusual signals indeed, but pretty efficient in the use of space. I wonder if they are unique to this line?

johnbresnahan10 Wrote:
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> Thanks for the info. They are unusual signals
> indeed, but pretty efficient in the use of space.
> I wonder if they are unique to this line?


The Ex-SOO now CP line from Shoreham to Withrow also uses 4 head signal heads, and I think the Minneapolis-Paynesville line also.

This one is right behind my house.

-LD

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