Our family did this in June, along with MisterDisney and Kevin.
If your husband loves trains, he'll love this tour. You start out by going to the roundhouse, where they tell you all about how the steam train work, and the history of how Disney World came to acquire their 4 steam trains.
Then it's back to the platform, where you hear a story about how Walt himself was facinated by trains, starting from his earliest job as a newpaper and snack vendor on the trains, to when he built his own miniature train that ran around his house.
You also get souvenir Steam Train Tour pins. Very cool!