Nostalgia & History > Weekly Night Shot #19 - SP red Gyralight, Oakland CA

SP had red Gyralights on many of their locomotives.  However, I rarely saw one operating.  On March 4, 1982 at Oakland, however, somebody left the red light going on SD40R 7382, lighting up the flank of the 8315.
- Eric Blasko

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Someone being JDS?

Good guess!  But this time it wasn't.
- Eric B.

Didn't they only come on when the train was in emergency?

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espeefan Wrote:
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> Didn't they only come on when the train was in
> emergency?

Not only when in emergency. 

Since these "oscillating red lights", as they were called on the SP, were normally brake pipe air pressure activated, whenever that
air pressure dropped below, IIRC, 35 psi they would come on. This would commonly be during and after a emergency application
of the train brakes and required no action on the part of the engineer. When the brake pipe pressure was restored above 35 psi
the light would turn off.

But SP also used them in at least one other application. The 1960 edition of their rule book had a provision in one of the rules for
the oscillating red light, on engines so equipped, to be displayed when proceeding at restricted speed while following a flagman.
This, of course required them to be able to be manually operated, as well.
The rule referenced above disappeared from the 1969 SP book. 

Charlie