I have had an interest in theater pipe organs since I was young.   In 1962 and 63, I had the privilege of working with an older gentleman who had been a Wurlitzer theater organ repairman in the 1920s, who taught me about theater organs and how they worked.  
Theater Organs were used to provide the sound effects for silent movies and entertaining the crowd during intermission.   The main difference between a theater organ and a church or symphony organ is the extra musical instruments and sound effects that can be played from the keyboard and some types (voices) of pipes were different.   Some of the pipes in a theater organ were strings, wood winds, brass, vox Humana (like the human voice), flutes of many kinds, and many others.   Some of the other instruments played by a theater organ keyboard were pianos, cathedral chimes, orchestral chimes, hand bells, marimbas, glockenspiel, xylophones, vibraphone, harp, celeste, gun shots, wood blocks, car horn, siren, boat whistles, bird whistles, boat whistles, police whistles, castinets, tambourines, chinese gongs, base drums, trap drums, snare drums, and many many other devices, in other words there is almost no limit to the sound making devices found in a theater organ.   Almost any sound you can think of that might be in a movie could be produced by a theater organ, at least sounds heard before 1927.   For a sample of some of the sounds listen here.   These were found on, what a theater organist calls "the toy shelf".   There were also some differences in the particular voices (pipe ranks) between the theater organ has a Tibia rank and church organ has a Diapason rank, however some theater organs (like Buddy Cole's) had both.