July 1:  All arch bar railroad car trucks are banned from interchange.  [SAM]

Fall:  Oil is discovered about six miles northeast of Reed City.  later this field developed into one of the best in Michigan.  Loading tracks were constructed along Pere Marquette tracks in the west part of town by the Pure Oil Company and the Simrall Corporation.  An oil refinery of 3,500 barrels daily capacity is operated by the Osceola Refining Co.   [PM45]

December 31:  Michigan Railroad Mileage Totaled 7,303 miles.  [MDOT]

Sometime "Before WW II":  D&M abandons Prescott Division.   [HI]

MCRR abandons the Lansing Branch, between SPringport and Lansing.  [MRC-5/1981]

The New York Central abandons the Air Line main line between OD Tower and Haires, near Jackson.  Up to this time, the Air Line had been used as the west bound track along side the Fort Wayne Branch (which was eastbound), as double track between OD and Haires.  [GB]

In the Transportation Act of 1940, Congress eliminates the discount for carrying passengers and mail on land grant railroads (which were instituted in 1876).  A discount of 50% off regular rates was continued until 1945.  [AAD]

The Copper Range purchases its first diesel engine. They now operate nine steam locomotives (down form 22 or more), and 1 diesel.  COPR retires it’s derrick. [CRH]

All wood under frame cars are outlawed.  [SAM]