The cartoon opens with Mickey piloting a steam engine, and ringing his bell, and blowing the engine's whistle. As the engine and his coal tender back to collect a boxcar, the engine rests with Mickey, his railroad engineer, fuelling him, and feeding his engine with coal from the tender. As the engine eats too much coal and burps, Mickey decides to have some spaghetti, until Minnie comes along. After Mickey finishes his lunch, Minnie arrives with a violin that she can play, and hops onto the freight car. Minnie plays a musical song while Mickey does the same. As Mickey looks at his watch, only to realize that they are late, he yells 'All aboard!' to the engine, which whistles in cheerful response after Mickey gets on board. The engine slowly starts out of the station and chuffs cheerfully through the beautiful countryside toward a hill and struggles up it. The engine ends having problems and starts to cry until the cartoon ends with Mickey pushing the boxcar too hard that it comes loose from the engine, runs into Clarabelle Cow, and explodes; Mickey and Minnie emerge from the wreckage riding a handcar (made from the chassis and a plank of wood from the freight car which came uncoupled accidentally when Mickey tried to push the train up the hill when it got stuck earlier in the film) into the sunset.
The cartoon shows Mickey's engine of the train in which he pilots as being an 2-2-0 engine or a Planet type steam locomotive.
These types of locomotives of this wheel arrangement were built only during the pioneer railroad days, circa 1830. These types of engines have four wheels on their tender and have wheels, such as two leading, two driving wheels, and no trailing wheels. Usually, a steam locomotive's tender would have four wheels, except Mickey's Planet type engine, who only has two wheels on its tender.
The makeshift handcar seen in the ending of this short inspired a similar toy made by the Lionel Corporation, who made so much money from it that Mickey was known as "the mouse that saved Lionel".