Maybe a guy shouldn't believe everything he hears, but the trouble with some people is that they don't even believe a true story. Let me buy you a beer and tell you about it.

After working some years in the baggage room of the local depot, I decided to transfer to the train service, and made application for it. The application was approved. I was sent to the city offices for the course of study and training which all trainmen undergo, and after a time I was sent out as brakeman on a freight. I stayed for a year and a half. Then I succeeded in being assigned as head brakeman on a fast food special called The Red Ball Special. It made no stop between Chicago and New York except for water and fuel. The big Diesel in which I rode as head brakie was a high-speed locomotive, used exclusively for hauling the food special.

Our first stop was Detroit, where we cut off all but three cars, and took on five more scheduled in New York at 9 the next morning. In New York, I strolled along Broadway, gawking at the sights exactly like any other yokel.

After a twelve-hour rest, the return trip began. I stood in my place in the big Diesel till we had cleared for the main line, and then settled back to enjoy the ride.

It was close to midnight. I sat at the cab window half asleep, my senses somewhat dulled by the steady rhythm of train movement. I'd finished an extra good cigar and had started to doze off when the engineer gave a low moan and toppled from his seat to the floor of the cab.

The fireman, much against the rules, but feeling safe with the engineer and myself to watch in his place, had gone back to inspect a suspected leaking air hose without waiting for the train to stop.

I got the engineer back on his seat. He was dead.

I tied him in place and then began pulling on the whistle cord like mad. It was not my work to operate a Diesel. I'd not troubled to learn.

I wondered why the fireman did not get back. I was going to jump, although I didn't like my chances at that speed, when I suddenly discovered a strange man in the cab with me. He was a pretty ordinary little guy, except for a wild, shaggy head of hair.

"You chump!" he squeaked at me. "Maybe next time you'll obey the rules, and not sneak by without finding out things! See that short rod with the spring-clip? Squeeze that clip and pull the rod back. Move, you fathead!"

I did as the shaggy man told me, and felt the speed of the train slacken slightly as the power went off.

"Now, that brass handle sticking out of that pipe—move it to the right slowly. Slowly , you dunce!"

Nine cars and the Diesel ground slowly to a stop. The wheels shuddered and skidded slightly because of my inexperienced hand, but the train did stop.

The stranger nodded in satisfaction. "When you get back home, bone up on things. But right now you go take a close look at the manifest card on the sides of the second and third cars...."

I jumped to the ground to go back and look at the second and third cars. As I passed the rear of the Diesel I saw why the fireman had not come back to the engine cab. All that was left of him was the lower part of his body. He had slipped, caught one foot and gone under the wheels.

I came to the second car and read the manifest label. My hair stood straight up.

The cars were marked:

Danger
DYNAMITE
High Explosive

The shaggy man was at my side. "You've got questions. But let me ask you one: Ever hear a story about how if you travel back to the time of an ancestor and you let him die you never get born?"

"What about it?" I said.

"It's true," said the shaggy man.