Wasn't D. B. Cooper the airliner high jacker who was never found? He parachuted out of a B727 with $200,000 in 1971. https://en.wikipedia.org/wiki/D._B._Cooper. He was younger than your grand dad.
Yea Grandpa said he and about 15 other DB Coopers never heard the end of it lol. He was a great Grandfather to me. Got me my first ride on a GP7 like that one. Ruined me 4 ever too.
(Very) Late to this party... Good for your Grandpa! I'll be that ride set the hook forever in you to love railroads and railroading! My first cab ride was courtesy of a Hostler I can't remember, but the dad of my friend Lee Ulick(sp?) worked for the Rock Island at the Rock Island's Armourdale Yard in KS. He took son Lee and I down to see the trains up close and personal. In the process of the afternoon (morning?), we got to ride with the Hostler as he moved about some high hood Geeps. This would have been about 1957 or '58, I think. Though I liked trains long before that, I reckon that one set the hook in me to be coo-coo for trains the rest of my life.