Porky is informed that his beloved train, the No. 13½ engine named Toots the 15th Century Unlimited, is to be replaced by a streamlined train by the name of Silver Fish. After the driver of the Silver Fish insults Toots, Porky mutters that his train could easily take on the steamlined train. The driver agrees to a race that ends with Porky being the victor (thanks to a bull seeking revenge on Porky after previously being insulted by him) and becoming the new driver of the Silver Fish whilst a battered Toots is on a trailer behind with "Headin' for the Last Roundhouse" written on a sign attached to it.
On Nickelodeon airings, omitted from all three versions of this cartoon (the original black & white, redrawn colorized, and computer colorized versions) was the scene where the Silver Fish races by a woodpile and a little black man is revealed, referring to a racially offensive saying. In the redrawn version, the scene with the Silver Fish going through a tunnel and turning it inside out was also gone. In addition, there was sometimes a false "iris-out" so that this cartoon would end with Porky's train flying over the finish line and the crowd cheering. deleted was Porky as the new engineer of the Silver Fish. Probably cut for time.
- During the race, Porky runs over the top of a boat called the 'S.S Leon', a gag dedicated to the cartoon's producer Leon Schlesinger.
- This cartoon reveals that Porky Pig is afraid of bulls.