- Component Products
 - Schaumburg - Manufacturer of traffic signal poles, shrouds, polycarbonate framework, and more. - Universal Coach Parts
- Des Plaines
- Chicago South Shore and South Bend Railroad
- Michigan City - 87 mile short line freight service carrier connecting Northwest Indiana's industrial complex with 19 railroads, including those within the Chicago Switching District.
- Chicago Trolley & Double Decker Company
- Chicago - Offers daily tours or special charters.
- Parking Block Store
- Hillside - Sells parking blocks, guides, speed bumps, safety signs, and cones.
- Illinois Central Corporation
- Holding company whose principal subsidiaries are freight railroads the Illinois Central (ICRR) and the Chicago Central (CCP).
- Midwest Transit Equipment
- Kankakee - Sales and service for new and used buses. Focuses on the transportation needs of childcare centres and schools.
- Miner Enterprises Inc.
- Geneva - Designer and manufacturer of railcar components including high capacity draft gears, constant contact side bearings, heavy-duty discharge devices, custom unloading systems, and brake beams.
- Astro Optics Corp.
- Carpentersville - Manufacturer of pavement markers, reflectors, guard rail and barrier delineators, and other channelizing devices.
- Tie and Track Systems, Inc.
- Lemont - Manufacturer of steel railroad ties, turnouts, bridge deck, yard, and more.
- Standard Car Truck Company
- Park Ridge - Designs freight car truck stabilizer systems and bogie components.
- Lawrence Ricci Industrial Equipment Services
- Steger - Maintains, repairs, and rebuilds all makes of mobile railcar movers.
- Virtual Transportation Management, Inc.
- Aurora - Provides third-party transportation information services including accounting, auditing, and electronic data exchange.
- United Transportation Group
- East Chicago - Offering liquid and dry bulk trailer cleaning, truck repair, rail tank and hopper car cleaning, and transloading services.
- Lothair Inc.
- Blue Island - Specializes in business communication for freight and passenger transportation industry. Services include media relations, advertising, direct mail, and more.
- ELCON, Inc.
- Frankfort - Designing, building, and servicing control systems for the railroad industry.
- Stimsonite Corporation
- Niles - Manufactures and markets reflective highway safety products.
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