While Walt Disney sadly passed away before the Magic Kingdom opened, he was deeply involved in the development of the railroad system. He was a lifelong enthusiast of trains and had envisioned a railroad running through the park.
While the current version of the railroad was completed after his death, it was built with his vision in mind, and is a direct descendant of the steam locomotive "Lilly Belle" which Walt personally had built for his own private railroad at his home in California.