The Carolwood Pacific Railroad

https://commons.wikimedia.org/wiki/File:Waltlayout.gif

Walt Disney loved trains. In 1947, when he showed off his Lionel set to animators Ward Kimball and Ollie Johnston, they revealed that they had ridable sets in their backyards. So two years later, when Disney bought 5 acres in Los Angeles, he set about building his own ridable railroad, 2,615 feet long and completely surrounding the house. To placate his wife, he named the locomotive after her and added an S-curve tunnel to avoid her garden.

Disney retired the train in 1953 when a derailment left a 5-year-old girl with steam burns, but he credited the Carolwood Pacific Railroad with inspiring Disneyland, which is encircled today by a narrow-gauge steam railroad that draws 6.6 million passengers a year.