A mouse named Bigelow, whom Snagglepuss once freed from a mousetrap, is intent on freeing Snag from a zookeeper, despite the fact that the lion doesn't want to be freed. The main action takes place on a train, hence the title.

After a flea is "evicted" from a dog's hide, kind-hearted Yakky offers to let the flea live on Chopper.

The army has its war games in a sealed-off part of the park; when Yogi wanders in, he thinks Jellystone has been invaded.

The bears' fairy godmother grants Yogi the power to turn anything he touches into a picnic basket (à la Midas).

Snagglepuss is being transported to the zoo on a riverboat; he escapes from his cage and poses as a riverboat gambler.

Sick and tired of being part of a lion taming act, Snagglepuss runs away from the circus and goes back to the jungle, expecting to be the king of the beasts.

Alfy Gator, in his first appearance, tries to catch Yakky so the 'gator can dine on roast duck.

Cindy Bear is in a circus, so Yogi runs off to join it; the circus owner get him a job as a lion tamer.

Ranger Smith tries to trap Yogi with an alarm-rigged picnic basket, and fails; later Yogi mistakenly thinks the Ranger wants him shot.

A railroad company tries to put a track through Snagglepuss' cave, but Snag thwarts their efforts; the railroad then hires Major Minor to handle the situation.

At the county fair, Snagglepuss is tired of being the target in an "African Dodger" type of game; he's talked into boxing with a kangaroo instead.

Chopper gives Yakky a trading stamp so his book will be completely filled, but the wind keeps blowing the stamp away from them.

Using a child's chemistry set, Fibber Fox creates a formula that shrinks Chopper down to Yakky's size, and the fox chases after the two of them.

Chopper and Yakky stay in an abandoned house for the night; Fibber Fox disguises himself as a ghost, hoping to scare Chopper away so he can catch Yakky.

When Ranger Smith goes on vacation, his seat is filled by Ranger "Iron Hand" Jones, who's more of a strict disciplinarian than Yogi can stand.

A Japanese bear who's a martial artist is transferred to Jellystone, and Yogi gets him addicted to picnic baskets.

An outlaw is intent on shooting the sheriff of a western town; after their sheriff runs away, the people appoint Snagglepuss their sheriff.

Bigelow the Mouse (from the Snagglepuss cartoon "Express Trained Lion") helps Yakky to stay out of Fibber Fox's clutches.

When a kiddie train is added to the park, Yogi becomes determined to ride it.

To evade hunters, Snagglepuss disguises himself as a soldier and winds up in an army camp.

A mad scientist switches Chopper's and Yakky's brains, and the two of them drive Fibber Fox crazy.

The military builds a secret rocket-launching base in Jellystone, and Yogi, Boo Boo, and Ranger Smith all wind up inside a space-bound rocket. This cartoon contains a great deal of satire of the military.

Snagglepuss visits an old English castle, which is haunted by a pair of mischievous ghosts.

Yakky and Chopper enjoy a day at the beach, until Fibber Fox starts chasing after Yakky again.

Yogi and another bear compete for Cindy's affections by bringing her gifts, committing a rash of thefts throughout the park in the process.