| Abbreviation | Definition |
|---|---|
| ASAB | Bay Line Railroad L.L.C. |
| ASB | Armor-Swift-Burlington |
| ASCV | Adirondack, Susquehanna, and Chenango Valley Railroad |
| ASCX | Algoma Steel Corporation (Armco Steel) |
| ASCX | Armco Steel Company L. P. |
| ASDA | Asbestos and Danville Railway |
| ASDX | Allied Services |
| ASFX | American Steel Foundries |
| ASGX | Ash Grove Cement |
| ASGX | Ash Grove Cement Company |
| ASHU | Maritainer France |
| ASHX | American Soda |
| ASLX | Algoma Steamships |
| ASML | Atlanta, Stone Mountain and Lithonia Railway |
| ASMX | Ames And Sons Machine Works |
| ASR | Allegheny Southern Railroad |
| ASR | Allegheny Southern Railroad Incorporated |
| ASRW | Allegheny Southern Railway |
| ASRX | Amstar Corporation (Domino Sugar) |
| ASRX | Domino Sugar Company |