In 1973, Six Flags Over Texas added Goodtimes Square to the park. With the new area addition, Boomtown Depot's name was changed to Goodtimes Depot and sat near the beginning of the Goodtimes Square section.
When the Mr. Freeze roller coaster made it's 1997 entrance into the park, Goodtimes Square essentially shrunk to allow the eventual Gotham City section of the park to be created. With this change the Goodtimes Square Depot was absorbed back into the Boomtown section of the park and renamed back to Boomtown Depot.
Today, however, you may find some of the theming from Goodtimes Square Depot (take a look at the water tower near the railroad crossing).