The distant footage of Homer Bedloe running the handcar is in black and white. Most likely the footage came from the first two seasons, when the show was black and white.
Near the beginning of the episode, when it shows the Cannonball uncoupling from the car, after it pulls away from the car, part of the footage is run in reverse, as you can see the smoke going into the smokestack.
When the Cannonball breaks through the "Welcome, Hooterville Cannonball" sign, it looks like a model train, rather than a real train.
The nighttime shots of the Cannonball (when the kids are on the "all night party" train), look like a model train, rather than the real train.