In the depths of the depression, many American companies were on the ropes. If you cannot afford food, you probably aren't worried about buying toys or other items. You certainly wouldn't be buying toy trains. Lionel Train Company was falling victim to the financial collapse and in dire straits. Things looked very bleak.
Enter a plucky mouse named Mickey. Lionel decided to license Mickey and Minnie for a novelty handcar that ran around a circular track. The toy was a smash success, selling out nationwide. Lionel was saved.
Mint condition handcars, complete with the circular track can sell for $5000 today. Any surviving handcars can fetch at least $750 regardless of condition.