1899
- February 24, 1899 – Aurora & Chicago Railway Company and the Elgin & Chicago Railway Company are incorporated by the Everett-Moore syndicate
- February 25, 1899 – The Chicago, Wheaton & Aurora Railroad Company is incorporated by the competing Pomeroy-Mandelbaum syndicate
- March 11, 1899 – Aurora, Wheaton & Chicago Railway Company incorporated (Everett-Moore syndicate)
- October 2, 1899 – City of Aurora grants the AW&C a franchise
- March 24, 1900 – President Lewis of the Cicero Board of Trustees vetoes the ordinance granting the AW&C a franchise
- March 31, 1900 – Cicero Township grants the AW&C a fifty-year franchise
- April 12, 1900 – Village of Harlem (Forest Park) grants the AW&C a fifty-year franchise
- August 23, 1900 – City of Elgin grants the Elgin & Chicago Railway a fifty-year franchise
- February 21, 1901 – Batavia & Eastern Railway Company incorporated (Everett-Moore syndicate)
- March 12, 1901 – Second annual meeting of the AW&C. Stockholders change the corporate name from the Aurora, Wheaton & Chicago Railway Company to the Aurora, Elgin & Chicago Railway Company.
- May 16, 1902 – First inspection trip held
- May 17, 1902 – Batavia Power house boilers lit for the first time. Certain imperfections come to light and are remedied.
- June 23, 1902 – Chicago City council passes an ordinance allowing the Metropolitan West Side Elevated to construct a terminal at Van Buren Street and Fifth Avenue
- July 29, 1902 – First six cars are delivered from the Niles Car & Manufacturing Company
- August 25, 1902 – The Aurora, Elgin and Chicago (AE&C) begins regular service from Aurora to 52nd Avenue (Laramie) in Chicago. Passengers are required to transfer to Garfield Park trains of the Metropolitan West Side Elevated to reach downtown Chicago.
- Late September 1902 – Service begins on the Batavia branch
- May 29, 1903 – The Elgin branch is placed into service
- August 30, 1904 – Parlor-buffet service begins
- February 9, 1905 – The Metropolitan asks for the passage of an ordinance permitting AE&C trains to operate over the “L” to the Fifth Avenue Terminal and the Metropolitan to operate over the tracks of the AE&C to the Desplaines River
- March 8, 1905 – AE&C ends local service between Forest Park and 52nd Avenue and begins operating to downtown Chicago over the Metropolitan West Side Elevated. The Metropolitan extends Garfield Park rapid transit service west from 52nd Avenue to Forest Park.
- November 23, 1905 – Cook County & Southern Railroad is incorporated
- March 18, 1906 – The Cook County & Southern Railroad (Mt. Carmel branch) enters service
- March 26, 1906 – The Elgin, Aurora & Southern Traction Company (the Fox River Lines) and the Aurora, Elgin & Chicago Railway (the Great Third Rail) are formally consolidated into the Aurora, Elgin & Chicago Railroad
- August 27, 1908 – Chicago, Wheaton & Western Railway is incorporated
- September 21, 1909 – The Chicago, Wheaton & Western Railway begins service with AE&C third rail equipment over what would later be known as the Geneva branch. Trains only operate as far as West Chicago
- December 1909 – Chicago Wheaton & Western extends service to Geneva
- August 25, 1910 – Chicago Wheaton & Western extends service to St. Charles
- October 28, 1910 – Chicago, Wheaton & Western Railway is deeded to the Aurora, Elgin & Chicago Railroad
- March, 24, 1913 – Fire destroys the general offices in Wheaton
- September 14, 1915 – New Aurora Terminal opens in the Hotel Arthur building
- July 30, 1919 – Employees strike
- August 9, 1919 – AE&C is forced into involuntary bankruptcy. Joseph K. Choate is named receiver.
- August 21, 1919 – Strike ends
- November 11, 1919 – Judge Evans grants the Northern Trust Company permission to file a bill of foreclosure against the AE&C
- March 16, 1922 – R. M. Stinson and Thomas Conway Jr. purchase the AE&C's Third Rail Division
- July 1, 1922 – The Third Rail Division of the Aurora Elgin & Chicago Railroad is reorganized as the Chicago Aurora & Elgin Railroad (CA&E)
- May 24, 1924 – The Western Motor Coach Company is incorporated
- July 15, 1925 – Chicago Westchester & Western Railroad is incorporated
- March 4, 1926 – Samuel Insull assumes control of the CA&E
- October 1, 1926 – The CRT begins rapid transit service on the Westchester Branch. The CA&E ends local service between Forest Park and Bellwood
- October 31, 1926 – The CA&E ends passenger service on the Mt. Carmel (Cook County) Branch due to close proximity to the new Westchester service
- November 1, 1926 – CA&E begins motor coach service connecting Mt. Carmel Cemetery with the Westchester “L” station
- January 1, 1927 – 420-series cars ordered from the Cincinnati Car Company
- October 29, 1929 – Stock market crashes
- November 23, 1929 – Grand opening of the new Villa Park station
- December 1, 1930 – Westchester branch is extended from Roosevelt to 22nd & Mannheim
- April 1931 – Transfer bridge connecting the Wells Street Terminal and the Quincy “L” station opens
- November 28, 1931 – Dedication of new Poplar Avenue station
- June 7, 1932 – Samuel Insull resigns from CA&E Board of Directors
- July 21, 1932 – CA&E enters receivership
- March 30, 1935 – Aurora, Elgin & Fox River Electric operates its last electric trolleys
- October 31, 1937 – Last regular trains operate over Geneva Branch
- December 31, 1939 – Final Aurora Terminal opens
- November 28, 1941 – 450-series cars ordered from the St. Louis Car Company
- December 7, 1941 – Bombing of Pearl Harbor by the Japanese
- April 7, 1942 – 1905 agreement allowing the Aurora & Elgin use of the “L” to gain access to Chicago expires. No new agreement written since both companies (CRT and CA&E) in receivership. Operations continue without formal agreement.
- November 10, 1944 – Employees strike
- October 3, 1945 – First three 450-series cars arrive
- December 10, 1945 – 450-series cars enter revenue service
- June 28, 1946 – The Chicago Aurora & Elgin Railway Company and the Chicago Aurora & Elgin Real Estate Liquidating Corporation are incorporated
- October 1, 1946 – Chicago Aurora & Elgin Railway Company assumes operation of the Chicago Aurora & Elgin Railroad. Employees strike.
- October 16, 1946 – Strike ends
- October 1, 1947 – The newly formed Chicago Transit Authority assumes control of the rapid transit system
- January 29, 1951 – Employees strike
- March 10, 1951 – Strike ends
- October 8, 1951 – CTA board votes to replace Westchester “L” service with buses
- November 15, 1951 – The Illinois Commerce Commission refuses the CA&E's petetion against the Van Buren street-level relocation
- December 9, 1951 – CTA ends service on the Westchester branch and instates AB skip-stop service on the Garfield route. The CA&E resumes local service between Bellwood and Forest Park.
- June 25, 1953 – Construction begins on new transfer station at Forest Park
- September 20, 1953 – The CA&E ceases operations to the Wells Street Terminal and begins terminating trains at Desplaines in Forest Park. Service over the Batavia branch is reduced to Monday-Friday rush hours only. St. Charles/Geneva motor coach service is extended to Batavia at all other times.
- July 3, 1957 – The CA&E ceases all passenger service at 12:13 PM
- June 22, 1958 – Congress rapid transit line begins operating in the median of the new superhighway
- April 29, 1959 – CA&E files a petition with the Illinois Commerce Commission to abandon freight service
- June 9, 1959 – Illinois Commerce Commission authorizes the CA&E to suspend freight service the next day
- June 10, 1959 – Freight service is “suspended”
- July 6, 1961 – CA&E is officially abandoned at 5:00 PM
- 1967 – Poplar station is burned down
1970
- July 5, 1976 – Villa Park and Ardmore stations are dedicated by the Villa Park Bicentennial Commission
1980
1990
- October 1991 – Aurora Terminal platform is demolished
2000
2010