Crossing signals mimic swinging red lantern!

A RR puzzle:

Why do "mee-mool" lights (o)=(o) flash back and forth?

It's not justo attract attention or for visibility.
There is another reason!

If I understand your question. That is done so they are easier to see.
http://mc.net/hyden/images/crossarm.gif
Steve Irwin
February 22nd 1962 - September 4th 2006

That would be my guess too. Generally flashing lights get your attention faster than say, a solid light.

I can't remember where I heard this, or if its true or not, but they flash alternately like that to mimic the wigwags that would swing back and forth.

Sounds right to me. They "jump" back & forth, sort of like a person swinging a torch or lantern back & forth as a warning not to proceed. The light bars on police cruisers have the same effect, left-to-right motion.

YES!

To mimic the crossinguard's red lantern swinging right and left.

The Magnetic Flagman company produced electric "wig-wag" signals.

The wigwag had a few faults:
If either of the electromagnet coils fails, the signal's paddle will not swing and bell will not ring.
The swinging paddle causes a lever to move a clapper to sound the bell athend of each swing.

Also, the double-sided red lens in the middle of the paddle allowsunlight
from behind to shine righthrough.

There are three wigwags in use at private RXR crossings on the line between Goleta and Oxnard, CA.

I have never seen a wigwag signal mentioned in any drivers manuals!