WASHINGTON (AP) – James (Cool Papa) Bell got his nickname for being a calm guy. But when it was game time, the baseball player ran like lightning.

Bell was among the black baseball heroes in Washington back when the sport was segregated. William S. Keyes was among the adoring fans who paid 25 cents to watch them at Griffith Stadium.

"Oh my goodness. It was a heck of a feeling," said Keyes, an 87-year-old retired teacher who contributed to the show. "You were busting out with pride."

"Separate and Unequaled: Black Baseball in the District of Columbia" opened this week at the Historical Society of Washington, DC, and runs until October 5. More than 50 photographs, paintings and artefacts show how teams such as Bell's Homestead Grays built a thriving baseball culture in the nation's capital. The DC-focused show is supplemented by a travelling exhibit from the Negro Leagues Baseball Museum in Kansas City, Missouri, which covers the history of the leagues around the country.

"The idea for this exhibit is Washington has always been a big baseball town," said Gail Lowe, a historian at the Smithsonian Institution's Anacostia Community Museum, which curated the exhibit.

After the Civil War, baseball took off and teams were often segregated. Well-known black teams included the Washington Mutuals and the Alert Base Ball Club, which both counted Charles Remond Douglass – son of statesman, author and abolitionist Frederick Douglass – as a member. The teams played on white-owned fields such as the White Lot, named for a white fence that surrounded it.

The White Lot, now the site of the Ellipse, the grassy area in front of the White House, banned black players in 1874. But neighbourhood and amateur teams – with names like the Georgetown Teddy Bears and the Oriental Tigers – continued to sprout into the 20th century.

Pro baseball got a push locally with the opening of Griffith Stadium in 1891 at 7th Street and Florida Avenue in Northwest, home of the American League's Washington Senators. The exhibit includes two of the stadium's original green wooden chairs, a reminder of the ballpark's segregated seating. The stadium was torn down in 1965, and Howard University Hospital was built on the site. The Grays were among a long line of black teams that rented Griffith Stadium for their own games. The team's heyday is portrayed in action shots of players such as slugger Josh Gibson, who led them to the Colored World Series in 1943 and 1944.

Players faced daily hardships that came with being black in Washington, including segregated trolley cars and public bathrooms. With most black teams striving to break even financially, players weren't paid much and did side jobs to sustain their first love. But a major obstacle they faced was finding practice spaces.

"They would practice on whatever fields that would accommodate them, and often the city would not accommodate them," said curator Anthony Gualtieri. "They would often write to them and say it's not available because a white team was using it or just say no."