Transtar, Inc.
Transtar, Inc. is a subsidiary of the United States Steel Corporation. It was organized in 1988 to own U.S. Steel's railroad and other transportation subsidiaries.
Transtar owns or has owned the following companies:
| Company | Acquired from | Date | Notes |
| Birmingham Terminal Railway | U.S. Steel | 1988 | Sent to Watco Companies in 2012, name changed from Birmingham Southern Railroad to Birmingham Terminal Railway. |
| Delray Connecting Railroad | National Steel Corporation | 2003 | Owned directly by U.S. Steel until 2005 |
| Gary Railway | U.S. Steel | 2009 | Created from unsold part of Elgin, Joliet and Eastern Railway |
| Fairfield Southern Company | U.S. Steel | 1988 | In-plant operation; subsidiary of Birmingham Southern Railroad |
| Lake Terminal Railroad | U.S. Steel | 1988 | - |
| Lorain Northern Railroad | Unknown | N/A | Operates in close relations with the Lake Terminal Railroad |
| McKeesport Connecting Railroad | U.S. Steel | 1988 | Ceased operations |
| Mobile River Terminal Company | U.S. Steel | 1988 | Subsidiary of Warrior and Gulf Navigation Company |
| Texas and Northern Railway | Lone Star Steel Company | 2007 | - |
| Union Railroad | U.S. Steel | 1988 | - |
| Warrior and Gulf Navigation Company | U.S. Steel | 1988 | - |
| Bessemer and Lake Erie Railroad | U.S. Steel | 1988 | Sold 2001 to Great Lakes Transportation LLC |
| Duluth, Missabe and Iron Range Railway | U.S. Steel | 1988 | Sold 2001 to Great Lakes Transportation LLC |
| Pittsburgh and Conneaut Dock Company | U.S. Steel | 1988 | Sold 2001 to Great Lakes Transportation LLC |
| USS Great Lakes Fleet, Inc. | U.S. Steel | 1988 | Sold 2001 to Great Lakes Transportation LLC |
| Elgin, Joliet and Eastern Railway | U.S. Steel | 1988 | Sold 2009 to Canadian National |