The various rail brotherhoods represent train employees. The Teamsters aren’t players in this game.
The Teamsters drove the trucks that competed with the railroads. He means the teamsters wanted to shut down the competition from the railroads.
I thought the adults were telling us the Teamsters were behind the scenes crippling the trains so freight would have to be handled by long haul truckers. When I was a kid, the roads were not so clogged with semis as they are now, so who knows? I do remember long, long trains when we traveled on road trips.