Renewal of CTA Milwaukee Blue Line Track Design-Build

The Milwaukee Elevated portion of the Chicago Transit Authority (CTA) Blue Line runs from Evergreen Portal, south of Damen station, to Logan Square Portal, north of California Station. This 2.2-mile elevated steel double-track structure was constructed in 1895. CTA awarded a $20 million design-build contract to renew the track north of Damen Station and upgrade the track alignment. The track renewal included replacement of all timber ties between the Damen Station and the incline to the Kimball subway, replacement of rail at the Damen curves and California Station, and realigning the Damen curves to increase train speed through the curves from 15 mph to 25 mph.

Lochner was the lead designer on the design-build team with Kiewit Infrastructure Company. Within this alternative delivery framework, Lochner prepared design and construction plans for the replacement of two miles of elevated timber track deck, including walkways. Between Damen and Western stations, there are two existing horizontal curves for which the operating speed is 15 mph. Lochner’s design changed the track alignment in these locations to reduce the curvature and raise the operating speed to 25 mph. Lochner’s design also eliminated current areas of roughness to enable trains to travel at full operating speed through the remainder of the project area. Lochner analyzed the curve realignment area to ensure that the existing structure is suitable for the new alignment and speeds. The increased speeds will also necessitate changes to the signal design; Lochner managed quality control of the signal changes for the design-build team. Lochner also assisted in the preparation of maintenance of street traffic plans for construction work that will take place above several major thoroughfares.

Construction began in late March 2014. Throughout the construction, Lochner provided construction services, responding to RFIs and reviewing construction submittals.