Nice job, Randy! Last summer I saw a very similar tower in use at the Huckleberry Railroad - an 1880s line near Flint, MI. Unfortunately, I didn't get pictures of it, but will rectify that the next time I stop down there.
We stopped there early in the summer - the tank had been emptied for the winter, and hadn't totally swelled back up - there was still some leakage from the joints.
Keep up the good work!