The AT Park organ, according to the article, is a Hammond B-3 electric organ. These are very common in large institutions such as universities and major league ballparks.
The organ at Wrigley Field was built by the same company (Hammond) but it's model is called a "Wurlitzer" pipe organ because it uses pipes instead of electromechanical valves for its sound generation system. These organs can be found in large institutions such as museums and minor league ballparks.
Finally, there is a "Tutti-Frutti" organ at Dodger Stadium that was made by Nelson Organ Company. This model uses hydraulic pistons instead of electromechanical valves so it can be smaller than an electric organ and still produce rich sounds.
All three of these organs were installed before World War II, which means they use mechanical action pipes instead of electronic pumps for their sound effects. This means they can't be controlled by foot pedals or switches located on the console surface where the player would stand while playing.
Instead, the player controls the flow of water to certain groups of pipes using his/her right hand while reading music from a book or score with his/her left hand.
Only about half of big league ballparks still have live organ music during games. Coors Field had an organ until 1999. The instrument is still on display in the park's historical archives.
During that time, many ballparks had organs before they opened. One was built by Wurlitzer in 1956 and was located at Washington DC's Nationals Park until it was destroyed by fire in 2008. The company also built ones at Chicago's Comiskey Park (1956-1992) and Detroit's Tiger Stadium (1957-1990). Another one was built by Miller & Lux at LA's Dodger Stadium in 1990. This list doesn't include military bases or schools where organs were used for entertainment purposes rather than as teaching tools. These venues are listed in our section on musical instruments used in education.
There have been attempts to bring back this aspect of ballpark culture. In 2001, the Milwaukee Brewers announced plans to build a new stadium that would feature an organ played by musician Michael Morgan. However, after several years of delays the project has not moved forward and the team plays at Miller Park now.
In 2014, reports surfaced that the Colorado Rockies were considering buying an organ and putting it in their current home stadium.
Tradition. The organ was the only instrument that could accompany itself and fill a stadium before anybody thought of playing pre-recorded music.
It's the only sport that plays its entire season (except for World Series games) before a single play is made. Most major league games are played with two teams running their respective batting orders, but since 1884 all games have been completed before the first batter has stepped to the plate.
The organ provides the only constant sound during a game of baseball. It is used to signal batters to step up to the plate, to tell fielders where to go, and most importantly, to call strikes against the batter.
During timeouts players can be heard discussing strategy while coaches plot their next move. The organ also provides the only music during a game.
Baseball has had organs throughout its history. The first one was built by William Haughton in 1869 for $8,000 ($150,000 in today's money). It had 36 stops controlled by six men who played them using hammer dulcimers carved from wood taken from around the world. By 1893, when the American Association played its last season, every organ in the league had been destroyed or abandoned.
At sports events, organs The first organ used in a stadium in the United States was installed in Chicago Stadium in 1929. These might be linked to the public address systems that have been utilized in baseball stadiums since 1929. Wrigley Field premiered its organ, performed by Roy Nelson, on April 26, 1941. It remained in place through the end of World War II in 1945. After several changes of contractor, it was replaced in 1992 with an electrically operated pipe organ.
Today, only a few ballparks don't feature an organ. The most popular sport in the United States isn't available at all games; many baseball fans who want to witness an organ performance must travel to their favorite team's home town. Organs are found in the following major league stadiums: Baltimore Orioles, M&T Bank Stadium; Washington Nationals, Nationals Park; Chicago Cubs, Wrigley Field; Chicago White Sox, U.S. Cellular Field; Cincinnati Reds, Great American Ball Park; Cleveland Indians, Progressive Field; Colorado Rockies, Denver Coors Field; Detroit Tigers, Comerica Park; Houston Astros, Minute Maid Park; Los Angeles Angels, Angel Stadium of Anaheim; New York Mets, Citi Field; Philadelphia Phillies, Citizens Bank Park; San Diego Padres, Petco Park; Seattle Mariners, Safeco Field; St. Louis Cardinals, Busch Stadium; Tampa Bay Rays, Tropicana Field.