Late last year, the Illinois Department of Transportation awarded a $226 million contract to build up to 35 high-performance diesel-electric locomotives to a partnership formed by Siemens AG and Cummins Inc.
Caterpillar was a finalist for the project and Caterpillar officials believe they should have been picked.
Caterpillar filed a formal protest with IDOT last month, but it was denied.
According to the St. Louis Business Journal, Caterpillar has now filed formal complaints with the state's Procurement Policy Board and the Chancery Court in
Caterpillar says IDOT "unfairly evaluated and scored offers" while making its decision.