With the unmistakable towers of Chicago's Loop visible in the background, this Green Line train heads towards Ashland and 63rd.

A Green Line train crosses over in front of us at Tower 12 on its way to Ashland / 63 ST. Trump Tower stands in the distance.

The soon to be retired 2200 series cars hold track 4 as a outbound Red Line train rounds the 90 degree curve at Sheridan Rd on its way to Howard Street.

A Red Line train takes a trip around the turn loop at Howard Street.

It's almost quiet at the State/Lake Street station in downtown Chicago on a Sunday evening.

On a dreary and wet afternoon in the Windy City, a CTA commuter makes its trip around the unique L line.

The mainly glass Trump International Hotel and Tower sticks from the brick and mortar buildings which rise up around an outgoing L passenger train.

Two L trains meet at the corner. The view looking down puts perspective on how this system snakes trough the city.

Tight clearances as the L passenger cars just pass the corners of the buildings at one of the busiest railway crossings in the world.

Looking down on one of the busiest railway crossings in the world.

A CTA L train passes overhead on an early Chicago morning. Even the streets are empty at this hour.

This marks the 21st year of the Chicago Transit Authority's Holiday Train. Here the train sits at Midway shortly before going to the yard to be tied up for the night.

A third rail shoe arcs as a pink line train exits the loop bound for 54th/Cermak. Tower 18 has since been completely rebuilt with a more modern, streamlined look.

A CTA train crossing Wells Street bridge over Chicago River.