Good joke from my high school friend, Tom Painter!

Tom applied for a signalman's job on the railroad and met his new boss at the signal tower.
The boss gave Tom a pop quiz.
"What would you do if you realized two trains were heading towards each other on the same track?" he asked Tom.
"I'd switch one to another track," said Tom.
"What if the switch lever broke?", asked his boss.
"I'd run down the track and use the manual lever."
"What if the manual lever had been struck by lightning?" persisted the boss.
"I'd run back up here and use the phone to call the next signal tower," said Tom.
"What if the phone was busy?"
"I'd run down to the station and use the pay phone," replied Tom.
"What if the pay phone had been vandalized?" asked the boss.
Tom, tiring of this silly game, responded, "Well, I guess in that case I'd run into town and get my Uncle Leo."
The boss looked puzzled.
"Why on Earth would you do that?" he asked.
"Because Leo's never seen a train wreck," said Tom.