The cause of the overnight fire at the National Capital Trolley Museum in Silver Spring, Md., is not known.
A security alarm brought police and fire crews to the museum around 2 a.m. It took 50 firefighters nearly an hour to extinguish the fire.
Among the eight trolley cars lost was one from 1899. A 1935 trolley was a one-of-a-kind experimental model.
County fire investigators and members of the Bureau of Alcohol, Tobacco, Firearms and Explosives visited the scene and collected evidence, Montgomery County, Md., Fire Department spokesman Pete Piringer said.
A dog trained to detect fire accelerants was also brought in. Piringer said the dog was ``useful,'' but he added that a range of possible causes was being investigated, including the building's electrical system and a severe thunderstorm that rolled through the area.
A statement on the museum's Web site said plans were underway to build a new building for the destroyed streetcars - one that included sprinklers. The Museum hosts 20,000 visitors annually.
