Below is a list of all the locomotives actively tracked on HeritageUnits.com.
Atchison, Topeka and Santa Fe Railway
Chicago Burlington & Quincy Railroad
Duluth Missabe & Iron Range
Georgetown Rail Equipment Company
Knoxville Locomotive Works
Metro North Commuter Railway
Minnesota Commercial Railway
Missouri & Northern Arkansas Railroad
New York, Susquehanna & Western Railway
Railway Service Contractors Inc
Reading Blue Mountain & Northern Railroad
Spokane Portland & Seattle
The CIT Group/Capital Finance, Inc