In the early 20th century, the big building on the northeast corner of what is now West 25th Street and the westbound Interstate 10 frontage road was called a "roundhouse."

Although the building is round, it wasn't actually a house but a facility for servicing locomotives on the old El Paso and Southwestern Railroad.

The facility was an integral part of the railroad, which carried trains between Tucson and Douglas, and connected the tracks to the passenger depot at West Congress Street.

Jack Herman, 88, worked for the Southern Pacific Railroad, which merged with EP & SW, in the mid-1940s after he served in World War II.

The line served the mines in Southern Arizona, Herman said.

"It was primarily made for Bisbee, Douglas and Tombstone," he said.

The two railroads merged in 1924, according to Star archives.

The book "Railroads of Arizona, Volume One" says the roundhouse was equipped with 11 stalls, an 80-foot turntable, a cinder pit and a coal chute.

The book didn't state how many years the roundhouse was in service, but the passenger depot near Congress Street was open for 12 years before the railroads merged, according to archives.

Atko Building Materials operated in the building for about 27 years before the company closed the site last month, said Barbara Klasic, head of Atko's accounting department.

The company still owns the building, she said.

Contact reporter Jamar Younger at jyounger@azstarnet.com or call 573-4115.