Skokie Valley Route was a main line cutoff which ran through the Skokie River valley from Howard Street in Chicago to North Chicago Junction, parallel to U.S. Route 41. A freight interchange connection was made with the C&NW at Oakton Street in Skokie. The Skokie Valley Route was entirely double-tracked, located on private right-of-way, and utilized an automatic block signaling system. Power was supplied by a combination of third rail and overhead catenary, with the transition made between East Prairie Road and Crawford Avenue in Skokie. The Skokie Valley Route was constructed between 1923 and 1926, with the purpose of enabling high-speed limited-stop trains to bypass the increasingly congested Shore Line Route. From 1925 to 1948, the Chicago Rapid Transit Company (and later the CTA) operated local rapid transit service over the Skokie Valley Route between Howard Street and Dempster Street in Skokie. The Skokie Shops were also constructed along the Skokie Valley Route, and the CTA continued to utilize the line to access these facilities from Howard Street after local rapid transit service had been discontinued. Milwaukee Division The Milwaukee Division was a main line which ran from North Chicago Junction to Harrison Avenue in Milwaukee, and served the intermediate cities of Waukegan, Zion, Kenosha and Racine. A freight interchange connection was made with the Chicago, Milwaukee, St. Paul and Pacific Railroad (Milwaukee Road) at Racine. The Milwaukee Division was almost entirely double-tracked, aside from of single-track operation between Austin Avenue and Oklahoma Avenue on the south side of Milwaukee, and was located entirely on private right-of-way. The Milwaukee Division utilized block signaling, with automatic systems in place between North Chicago and Kenosha, as well as between Ryan Road in Oak Creek and Harrison Avenue, while a manual system was in place over the segment between Kenosha and Ryan Road. Power was supplied by a combination of overhead catenary and overhead trolley wire, with the transition made on the north end of Waukegan. Libertyville Division The Libertyville Division was a branch line which ran from Lake Bluff to Mundelein, parallel to Illinois Route 176. Connections were made with the Shore Line Route at Lake Bluff, and with the Skokie Valley Route at Green Bay Junction as well as at South Upton Junction. Freight interchange connections were made with the Elgin, Joliet and Eastern Railway (EJ&E) and the Milwaukee Road at Rondout, and with the Wisconsin Central Railway at Mundelein.