O’Hare Branch Signal Upgrades and Special Track

Chicago, Illinois

Mass. Electric Construction Co. — in a joint venture partnership with Kiewit Infrastructure Co. and Aldridge Electric — upgraded a 1980’s cab signaling system for 12 interlockings along the busy 8.5-mile O’Hare Branch of the CTA Blue Line.

The project scope included installing all new train signal and communications infrastructure along the active right-of-way and installing and commissioning 12 new signal houses/rooms — all while maintaining CTA’s revenue service 24 hours a day, seven days a week.

The project performed critical phasing and shutdown work over the course of the project schedule to minimize the effect of the transition from CTA’s existing system to activating the new signal system.