Western Railroad Discussion > UP caboose #25151

What are the red & green lights up on the coupola used for, and
how were they used? This one at the Van Horn, TX Chamber of Commerce.

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Both SP and UP had red and green markers on their cabooses. The red was used as the marker at the rear of a train, the green marker was used when a train was in the clear on a siding to let an approaching train know it was safe to proceed at the meet. If you look at older pictures of SP standard and bay window cabooses, they had the red and green marker lights on the roof.

Wow...that's a CA-4, originally built in 1944. It looks to be in pretty nice shape too!

The markers were for the crew to "communicate" with other trains. Red normally shown to indicate the rear marker and green if the train was in the clear in a siding and being overtaken by another train. Same as the old kerosene lanterns that had red and green lenses and could be rotated accordingly in their mount to show the correct aspect facing rearward.

I don't recall when the practice went "out of style" in North America. Probably sometime shortly after the mass adoption of automatic block signal systems. I'm sure someone here on TO knows more.

ArgyleEagle Wrote:
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> What are the red & green lights up on the coupola
> used for, and
> how were they used?

They take the place of externally-mounted marker lights. There's a three-way switch inside the caboose to operate them.

When rules required, the red light was displayed to indicate the rear car of the train. The green light was displayed when the train was operating in certain territory and was stopped in the clear of the main track, such as being in a siding.

If you've ever seen a photo of an SP caboose with two roof-mounted marker lights, originally one had a red lens and the other a green lens, and were displayed as described above. Eventually the rule requirement regarding the display of the green light was eliminated, and its lens replaced with a red one.

Does anyone else hear an echo in this thread......

On the SP they were called "Frog Eyes". They were used in the short period from rear markers (two mounted on either side on the rear) until the rule change that got rid of the green to the rear or side required by the old book. When the change was made, they were changed out where all of them were red and if one burned out, you had an extra. THEN, they went to one, front and rear and THEN, they took them off the roof and put them above the door. THEN, they took the lights, the hack they were on, and put the marker into a little bitty red flashing light that is known as "FRED".

And that is the end of the story, to date, today...?????? Stay tuned, it could change tomorrow.


Nudge

Now, it seems FRED is slowly being replaced with a DPU engine. First Coal, then manifest (granted only in the Blue Mountains, ut still), now I am hearing rumors UP is gonna do some experimintation with DPU on Stack trains out of Global 2.

LCW Wrote:
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> now I am
> hearing rumors UP is gonna do some experimintation
> with DPU on Stack trains out of Global 2.

Supposed to start test running 10,000-foot stack trains with DPU.

Similar in concept to when they tried running "double" stack trains with a manned helper on the rear between East LA and SLC.