The New Zealand Railways Magazine, Volume 6, Issue 2 (June 1, 1931)
An Unfailing Sniper
An Unfailing Sniper.
Thirty-six tall, shining levers stood up out of the floor like a row of rifles. The cabin might almost have been a sniping nest. Out there through the glass windows, dotted over the black, murky crisscrossed railway yard, with its coal-holes and its no-man's-land, were the signal-posts—fourteen of them. All of them within sight, just in case something goes wrong. Not that it will. That philosopher we mentioned, you know, didn't know much about railways —–
Now, watch. Down comes one of those block levers to set the points as the signalman pulls on it, then a blue to lock them, then a red, and—down comes the arm of that far signal, as if struck by a fatal shot. Now down with a couple of those black levers for the points, and a blue one for the lock bars, or a blue-and-black lever to work points and lock bars in one operation.
The way is clear, the road is set. Come on, you big puffing iron monster—you're a tank for which your unfailing sniper has cleared the way. Come on proudly with a roll of iron and a burst of steam.
Great shooting (if you will pardon the fantasy). Mysterious shooting. Every time the signalman pulls down a red lever he picks off one of those fourteen signal arms as clean as a whistle. And, far away, the points and the lock-bars on the railway lines jump to his distant command. Like the pieces of a cardboard puzzle being moved miraculously into place.
“Yes, but what about the element of human error?” I asked, without any tact whatever. “What if you pull down the wrong lever?”
The signalman smiled.
“That is just what you can't do Watch.”