http://www.txtransportationmuseum.org/IGN.htm
I was adding the building to Emporis and looked around for some reference sites. I found this one that has a lot of old pictures and postcards of the building. It talks about the history, all the uses and restorations. The building is turning 100 years old this year. I even found a height listed on that site, it's 88 feet tall. Check it out, they also have some neat pictures from inside during the restoration.
I am definitely going to have to go check it out the next time I'm in San Antonio.