With its office located in Steamboat Rock, Iowa, IARR carries corn byproducts and ethanol from Pine Lake Corn Processors to the interchange with the Canadian National Railroad in Ackley, Iowa.

In June 2006, the IARR also purchased from North Central Railway Association a rail line running between Steamboat Rock and Ackley, Iowa, which needed rehabilitation prior to operating over.

In 2012, the Iowa River Railroad filed to abandonment of line running from Steamboat Rock to Marshalltown with the Surface Transportation Board.

The same year, a request for imposition of a public use condition and issuance of an interim trail use for the line was filed on behalf of the conservation boards of both Marshall and Hardin Counties, as well as the cities of Marshalltown, Union, Steamboat Rock, Liscomb, Eldora and Albion and the Iowa Natural Heritage Foundation.

Current motive power had consisted of a single GP30, #3004, but has gained a recent addition GP38M, #3802.