Well, it’s been almost an hour since your post, so I’ll take a crack at it. I am a school teacher in Texas who also happens to drive a school bus on occassion. I have a Texas Class B CDL with passenger endorsement and school bus endorsement. To drive a school bus in Texas, one must also obtain a permit from the Texas Education Agency.
Some of my experience may apply to you because CDL’s, while issued by the several states, are regulated by the US Dept. of Transportation. The Class B allows me to drive single-unit vehicles in excess of 26000 pounds. A Class C (regular operator’s) license restricts drivers to under 26K. I cannot, however, drive articulated vehicles like 18-wheelers. The passenger endorsement allows me to have in excess of fifteen passengers (incl. driver) and the school bus endorsement is specific to school buses. The TEA card is a state thing, so it doesn’t apply to you.
To get the license, I took a class offered by my school district. The class was open to anyone who wanted to take it. Employees of neighboring districts also took the class. I don’t know how much the class is because my district paid for it (and paid me to take it). The class was twenty hours long and including tooling around the parking lot in a bus. After the class, I took the licensing tests at the local Department of Public Safety (DPS) office. The written tests took several hours and included things that had nothing to do with buses (including stuff like how to attach a semi-trailer, even though that had no application to my license). After the written test, I took a driving test around town in a school bus with a civilian DPS employee. This summer, I had to take another written test to get the school bus endorsement (this is a new federal law, so I didn’t take that test during the initial battery of tests).
With all of this, I could go into any metro transit authority in Texas and legally drive their equipment. However, each agency probably has training specific to its own equipment. Therefore, I would suggest that you call the transit company you want to drive for and ask how to make it happen. You could also call your local school, since they are probably always looking for drivers. That’s probably the cheapest and quickest way to get a license. Just remember that school bus drivers are driving the most precious and most dangerous cargo on the highway. Don’t drive a school bus just because you feel like it. Drive because you intend to offer safe transportation. I have friends who drive all sort of hazardous materials (yet another permit), but won’t touch what I drive. They’re not that brave.