Port Townsend, today. Ditch Lights were pioneered by the Canadian National Railways in 1955 or 1957. Today we see them in sleek lamp housings, along with other attention grabbing luminaries.
Ditch lights were NOT a factory option. They were added on in those divisions that had serious safety problems with rock slides, wash outs, and blind curves. They first appeared in Prince Rupert in 1957.
They were bolted on the hand rails of Geeps and SW1200RS's, and bolted to brackets mounted on cab units. And they were adjusted very scientifically - shining on the Engine House doors!
They were adjusted to cross beams 50 to 100 feet in front of the locomotive, giving the crew the effect of "seeing around a curve."
In those days, they were not about warning pedestrians or motorists. They were all about crew safety.
Pacific Great Eastern's RDC cars had them bolted on top of the cab!
I do not recall seeing them on Canadian Pacific engines at that time. None of my photographs taken in that era show any type of ditch lights on CPR locomotives.
And only those of you alive and well in 1957 can tell me what US roads were doing.
Obviously they became standard equipment and various light arrangements and flashing patterns have evolved.