On June 6, 1892, 125 years ago this week, the first elevated line called the "Alley L" opened for business, running from Congress Parkway and State Street to 39th Street, along the alley, behind and around buildings and through backyards, said Graham Garfield, CTA general manager of customer information and unofficial agency historian. The agency will be celebrating the anniversary with special events Tuesday, when a 1923 train will make several trips around the Loop from about noon to 1:30 p.m. Then, a train from the late '70s will travel the Loop for another 90 minutes. Riders can board at any Loop station, and regular fares apply, the CTA said.