Airport Tower Flashes Green Light to Arriving Train

Trains don’t fly, but one regularly received a green light from the airport control tower in the early 1950’s in Medford, Ore. It happened like this:
The Medford Corporation Lumber Company ran a daily log train from Butte Falls to its mill in Medford.  The Pacific and Eastern Railroad had built the tracks around 1910. That line passed down the east side of the airport, then across the incoming runway on the south edge of the airfield.
George Milligan, today known as the founder of Mercy Flights, was an air traffic controller at the time, a job described as “eight hours of boredom punctuated by moments of stark terror.” It was during one of the long stretches of boredom that Milligan had an idea.
He picked up the light gun that was used to signal planes that did not have radios whether they could land or takeoff. Milligan flashed a green signal to the engineer of the Medco log train. The signal was acknowledged with a wave. A good laugh broke the tension in the control tower.  After that, all the controllers began giving the daily log train an all clear to “fly through the control-zone.”
Source: Seeberger, Vic. "A green light for the flying train." Medford Mail Tribune 7 Dec. 2014, section c ed.: 1. Print.