| A&B |
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Attica & Buffalo Railroad Co. (The) |
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| A&B |
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Aurora & Buffalo Railroad Co. |
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| A&CR |
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Astoria & Columbia River Railroad Co. |
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| A&ERV |
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Auburn & Eel River Valley Rail Road Co. |
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| A&G |
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Asherton & Gulf Railway Co. |
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| A&GW |
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Atlantic and Great Western Railroad Co. (The) |
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| A&I |
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Auburn and Ithaca Railway Co. |
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| A&L |
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Atlantic & LaGrange Rail Road Co. |
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| A&LVE |
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Altoona & Logan Valley Electric Railway Co. |
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| A&MR |
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Arcata & Mad River Rail Road Co. |
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| A&N |
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Abilene & Northern Railway Co. |
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| A&N |
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Albany & Northern Railroad Co. |
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| A&NL |
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Ashtabula and New Lisbon Rail Road Co. (The) |
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| A&NR |
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Angelina & Neches River Railroad Co. |
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| A&NWRR |
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Austin & North Western Rail Road Co. |
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| A&NWRr |
|
Austin & NorthWestern Railroad Co. |
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| A&P |
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Ashtabula and Pittsburgh Railway Co. |
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| A&P |
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Atlantic and Pacific Railroad Co. |
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| A&R |
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Auburn and Rochester Railroad Co. (The) |
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| A&S |
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Abilene & Southern Railway Co. |
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| A&S |
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Albany and Schenectady Railroad Co. (The) |
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| A&S |
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Albany and Susquehanna Railroad Co. (The) |
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| A&S |
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Alton & Sangamon Railroad Co. |
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| A&S |
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Auburn & Syracuse Railroad Co. (The) |
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| A&STAB |
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Atlanta & St. Andrews Bay Railway Co. (Bay Line) |
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| A&T |
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Atchison & Topeka Railroad Co. |
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| A&WP |
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Atlanta & West Point Railroad Co. (West Point Route) |
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| AA |
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Ann Arbor Railroad Co. |
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| AB |
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Anderson Belt Railway Co. |
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| AB |
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Artesian Belt Railroad Co. |
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| AB |
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Asphalt Belt Railway Co. |
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| AB |
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Aurora Branch Railroad Co. |
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| AB-C&P |
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Akron Branch of the Cleveland & Pittsburgh Railroad Co. (The) |
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| AB&A |
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Atlanta, Birmingham & Atlantic Railroad Co. |
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| AB&C |
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Atlanta, Birmingham & Coast Railroad Co. |
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| AC |
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Algoma Central Railway Co. |
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| AC&HB |
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Algoma Central & Hudson Bay Railway Co. |
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| ACL |
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Atlantic Coast Line Railroad Co. |
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| AD&S |
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Austin Dam & Suburban Railway Co. |
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| AE&C |
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Aurora, Elgin & Chicago Railway Co. |
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| AL&S |
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Arkansas, Louisiana & Southern Railway Co. |
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| AM&O |
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Atlantic, Mississippi & Ohio Rail Road Co. |
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| AMTRAK |
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AMerican TRAcK (National Railroad Passenger Corp.) |
 |
| AN |
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Apalachicola Northern Railroad Co. |
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| AN&A |
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Alliance, Niles and Ashtabula Railroad Co. (The) |
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| AN&Y |
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Ashtabula, Niles and Youngstown Railroad Co. |
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| ARr |
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Alton Railroad Co. |
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| ARR&N |
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Acme, Red River & Northern Railway Co. |
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| AT&L |
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Austin, Todd & Ladd Railroad Co. |
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| AT&SFRr |
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Atchison, Topeka and Santa Fé Railroad Co. |
 |
| AT&SFRy |
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Atchison, Topeka and Santa Fe Railway Co. (The) |
| AV |
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Allegheny Valley Rail Road Co. |
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| AY&P |
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Ashtabula, Youngstown and Pittsburgh Rail Road Co. (The) |
|