Sure, George , dig out the link on these boats.

I'm looking for details of the drive train. Train is the operative word here. I'm certain that I am looking at something that would not be amiss connected to the drive wheel of a Locomotive. The engine really doesn't look like much of a difficult manufacturing proposition. Machines large enough to handle the castings would have been rare in the South.
You mentioned fuel stowage. I see how enough could be packed into the hull, providing a respectable range. The problem would be to get to it as you'd need it. How would one get past the boiler when it's hot?
I believe it was made plain to Lord Russell, the foriegn minister, that certain items shipped to the Confederacy would be considered an act of war. Locomotives, unlike arms, would be hard to conceal. Enough drive pistons to propel the forty boats Glassell wanted wouldn't have been a problem to ship. No doubt more shops in England able to machine the drive gears.