Donald Duck's nephews  Huey, Dewey and Louie  are trying to earn a merit badge in engineering for the Junior Woodchucks by working out a complicated problem involving toy trains.
(quoted from Train Brains / The Runaway Train (Donald Duck))
"We'll never be promoted to S.U.E.O.T.U. [Supreme Unsurpassable Engineers of the Universe] in the Junior Woodchucks if we can't figure how to keep two trains from colliding! This engine's wheels travel 3 1/2 inches each time around!"
"And it's 137 inches from the water tank to the switch head!"
"How many turns per second must it roll? Mm! Mm!"

The problem becomes quite complicated as they have to take into account the curvature of the track and the slippage of the wheels.
Then, by coincidence, an announcement is overheard on the television that Uncle Donald is watching in the next room:
(quoted from Train Brains / The Runaway Train (Donald Duck))
"LISTENERS EVERYWHERE, ATTENTION! WE MUST FIND PROF. BRAINWHIZ, THE GREAT MATHEMATICIAN, AT ONCE! ONLY HE CAN SAVE HUNDREDS OF LIVES IN THE NEXT FEW MINUTES! A RUNAWAY LOCOMOTIVE IS ROARING DOWN THE SIERRA GRADE, HEADED FOR A CRASH WITH THE LIMITED SOMEWHERE IN THE STORMSWEPT MOUNTAINS..."

Professor Brainwhiz is unable to solve the problem, as is the computer at the army base, but the three ducklings save the day.
Much thanks to Erik Holst in Sweden who pointed out this story and its mathematical content to me.
Erik points out that the math problem solved by the kids is very difficult (even the "great mathematician" could not do it) and so was not an elementary school level problem. However, the colliding trains is such a classical example of what we call a "word problem" in American school culture that I am certain the author was making an intentional reference to mathematics education. Either it was an attempt at (un)subtle propaganda (to get the children reading to think "Hey, math problems really are important!") or just a joke (wouldn't it be funny if some kids really had to work out one of these word problems to stop some trains from colliding!?!) But, maybe other readers disagree with me. What do you think? Please use the links below to enter your comments and votes.
There is more information on this comic at inducks.org.
Contributed by
Robert W. Franson
This story not only shows clear mathematical thinking by Huey, Dewey and Louie, it also shows effective action under pressure. A good story.

