Updated through online information from James R. Stettner.
From Robert Green: The organ was originally a tracker action instrument. However, in the 1950's Otto Hoffman from Austin TX put electro-pneumatic pulldowns on the chests. Most of the pipes are still original with a few alterations by Hoffman. Just yesterday I met a lady who remembers seeing water running down the curb from the church in the mid 1930s. She went on to say that this was from the water motor operating the bellows.