Kinzie Street near Paulina Avenue

This over-head trestle is a remnant of Chicago's mass transit-history.
Today, this 90+ year-old steel acts as a glorified signal mast for Union Pacific, Norfolk Southern, Canadian Pacific and Metra rails.

No modern-day railroad would invest in such a limestone foundation, the skilled workers to erect it (nor the labor to maintain it!). The trestle was designed to elevate a north-south line over an already elevated east-west main-line.