By 1886, the Wisconsin Central Railroad had formed a new railway company, called the Chicago and Great Western Railroad (C&GW) to build a new line from a connection with the WC at Forest Park into the city, and to construct the Grand Central Station, which opened in December 1890.
In March 1890, another subsidiary of the Northern Pacific Railroad bought the C&GW along with several other WC lines in the Chicago area, consolidated them all as the Chicago & Northern Pacific Railroad (C&NP). The next month, the WC had itself leased to the Northern Pacific. As they were both controlled by the same railroad, the C&NP and the C&CT were linked together with new construction and trackage rights. The lease arrangement between the Wisconsin Central and the Northern Pacific worked until the Panic of 1893, when the WC was freed from the lease, and the C&NP was again placed under the control of the WC. Weakened by the prolonged economic downturn, the C&NP was bankrupt by October 1893.
In July 1897, a new company called the Chicago Terminal Transfer Railroad (CTT) bought the C&NP from the Wisconsin Central. While the WC (and successor Soo Line Railroad) no longer had its own direct connection to the city, it continued to use the line to access Grand Central Station until 1899, and between 1912 and 1965. In May 1897, the Chicago Terminal Transfer merged the Chicago & Calumet Terminal. The B&O began using Grand Central Station in 1892, when a connection was made between the CTT and the B&O at South Chicago. When the Pere Marquette Railroad was completed to Porter, Indiana in 1903, it also used the CTT into Grand Central Station.
On January 6, 1910 the Baltimore & Ohio Chicago Terminal Railroad was created to purchase the CTT at foreclosure, giving B&O control of the both the terminal railway system, as well as Grand Central Station.
The railroad reached a peak size in the 1920s of 78 route-miles and 365 track-miles.