I used to work for ABB Transportation who made these things so I should
really know....but it's been a while :o)

I *think* the yellow aspect meant something like the next block section but
one is occupied so proceed with caution?

Also the red aspect is on the bottom, so that there is no hood from another
aspect underneath that snow could build up on and obscure the signal.  I
think.

Cheers

Mike Rigby-Jones


> What Dmitry refers to as an "eye" and others as a "lamp", is
> technically called an "aspect", particularly in railway use (as Anniepoo
> would know!).  Thus you have "single-aspect" or "three aspect" displays.
>
>   Speaking at least for this country, single-aspect railway displays
> are an oddity that has been around quite a while, originally in the form
> of the lamp on a semaphore with a moving colour filter.  Colour vision
> *is* a prerequisite for train drivers.
>
>   (Aside:  How many know what alternate uses the yellow aspect has in
> railway signals?  It certainly doesn't mean the same as in traffic
> lights!)
>
>