| 1 | B | Bamberger R.R. | 1/1941-7/1965 | NAKINA | |
| 2 | B | Bamberger R.R. | 1/52-7/65 | NRHS | |
| 3 | B | BAMBERGER RR | PWRC | ||
| 4 | B | NMBS/SNCB | BE | VKM | |
| 5 | B&A | Boston & Albany R.R. | 8/1920-10/1966 | NAKINA | |
| 6 | B&A | Boston & Albany R.R. | 7/23-10/66 | NRHS | |
| 7 | B&A | CONSOLIDATED RAIL CORP. [BOSTON & ALBANY RR] | PWRC | ||
| 8 | B&C | Barre & Chelsea R.R. Co. | 7/1923-1/1946 | NAKINA | |
| 9 | B&C | Barre & Chelsea R.R. Co. | 23-Jul | NRHS | |
| 10 | B&C | BARRE & CHELSEA RAILROAD CO. | PWRC | ||
| 11 | B&CW | Bennettsville & Cheraw R.R. Co. | 8/1920-1/1950 | NAKINA | |
| 12 | B&CW | Bennetsville & Cheraw R.R. Co. | 7/23-4/38 | NRHS | |
| 13 | B&CW | BENNETTSVILLE & CHERAW RAILROAD CO. | PWRC | ||
| 14 | B&G | Bingham & Garfield Ry. Co. | 8/1920-7/1936 | NAKINA | |
| 15 | B&G | Bingham & Garfield Ry. Co. | 23-Jul | NRHS | |
| 16 | B&G | BINGHAM & GARFIELD RWY. CO. | PWRC | ||
| 17 | B&LE | Pittsburgh, Bessemer & Lake Erie R.R. (Bessemer & Lake Erie R.R.) | 8/1920-7/1936 | NAKINA | |
| 18 | B&LE | Bessemer & Lake Erie R.R. | 8/1920-10/1966 | NAKINA | |
| 19 | B&LE | Bessemer & Lake Erie R.R. | 7/23-10/66 | NRHS | |
| 20 | B&LE | BESSEMER & LAKE ERIE RAILROAD | PWRC | ||
| 21 | B&M | Boston and Maine R.R. | 8/1920-7/1936 | NAKINA | |
| 22 | B&M | Boston and Maine R.R. | 23-Jul | NRHS | |
| 23 | B&M | *BOSTON & MAINE CORP. | PWRC | ||
| 24 | B&M | *BROWNSTONE & MIDDLETOWN RAILROAD | PWRC | ||
| 25 | B&O | Baltimore & Ohio R.R. Co. | 4/1938-10/1966 | NAKINA | |
| 26 | B&O | Baltimore & Ohio R.R. Co. | 4/38-10/66 | NRHS | |
| 27 | B&O | CSX TRANSPORTATION, INC. [BALTIMORE & OHIO RR] | PWRC | ||
| 28 | B&S | Baltimore & Ohio R.R. | 4/1938-1/1946 | NAKINA | |
| 29 | B&S | Buffalo & Susquehanna R.R. Corp. (Baltimore & Ohio R.R.) | 7/1932-7/1936 | NAKINA | |
| 30 | B&S | Buffalo & Susquehanna R.R. Corp. | 7/1923-7/1930 | NAKINA | |
| 31 | B&S | Buffalo & Susquehanna R.R. Corp. | 23-Jul | NRHS | |
| 32 | B&S | Baltimore & Ohio R.R. | Apr-38 | NRHS | |
| 33 | B&S | Bahn&Service | Walburg | D | privat-bahn.de |
| 34 | B&S | BUFFALO & SUSQUEHANNA RAILROAD [BALTIMORE & OHIO RR] | PWRC | ||
| 35 | B&SE | Birmingham & Southeastern R.R. | 4/1938-7/1965 | NAKINA | |
| 36 | B&SE | Birmingham & Southeastern R.R. | 4/38-7/65 | NRHS | |
| 37 | B&SE | BIRMINGHAM & SOUTHEASTERN RAILROAD | PWRC | ||
| 38 | B1 | JBSS Bahn 1x | TRAFFIC | ||
| 39 | B2 | JBSS Bahn 2x | TRAFFIC | ||
| 40 | B4 | JBSS Bahn 4x | TRAFFIC | ||
| 41 | B5 | Babylon 5 | Scifi film | TRAFFIC | |
| 42 | BA | Consolidated Rail Corp. | added 4/1976; 1/1980-1/1994; eliminated 7/1999 | NAKINA | |
| 43 | BA | Penn Central Transportation Co., Robert W. Blanchette, Richard C. Bond and John H. McArthur, Trustees | eliminated 4/1976 | NAKINA | |
| 44 | BA | Penn Central Transportation Co. | 1/1975 | NAKINA | |
| 45 | BA | Penn Central Transportation Co. | Jan-75 | NRHS | |
| 46 | BA | Penn Central Transportation Co., Robert W. Blanchette, Richard C. Bond and John H. McArthur, Trustees | eliminated 4/76 | NRHS | |
| 47 | BA | Consolidated Rail Corp. | added 4/76; 1/80-1/94; eliminated 7/99 | NRHS | |
| 48 | BA | CONSOLIDATED RAIL CORP. [BOSTON & ALBANY RR; PENN CENTRAL] | PWRC | ||
| 49 | BA | Boston and Albany Railroad (Conrail) | RSRV | ||
| 50 | BA | British Airways | Real: BAW | GB | TRAFFIC |
| 51 | BA&P | Butte, Anaconda & Pacific Ry. | 8/1920-7/1936 | NAKINA | |
| 52 | BA&P | Butte, Anaconda & Pacific Ry. | 23-Jul | NRHS | |
| 53 | BA&P | BUTTE, ANACONDA & PACIFIC RY. | PWRC | ||
| 54 | BAA | Balkan Agro Aviation | ICAO1 | ||
| 55 | BAAA | BUTLER, ARTHUR R | SCAC3 | ||
| 56 | BAAA | BAYMEADOWS MOVING AND STORAGE INC | SCAC4 | ||
| 57 | BAAB | B & A CHARTER TOURS INC | SCAC3 | ||
| 58 | BAAC | BARRON EXPRESS | SCAC4 | ||
| 59 | BAAE | BUDGET AUTO & EQUIPMENT SALES INC | SCAC3 | ||
| 60 | BAAF | BRODERICK AUTO & TRUCK | SCAC4 | ||
| 61 | BAAG | BALLENSKY, ALAN G | SCAC3 | ||
| 62 | BAAH | BRUCE A BOND PETROLEUM LTD | SCAC4 | ||
| 63 | BAAK | BANTA TRUCKING | SCAC3 | ||
| 64 | BAAL | BAR-LYNN STABLES | SCAC4 | ||
| 65 | BAAM | BENSTEAD, A & A TRUCKING LLC | SCAC4 | ||
| 66 | BAAN | BAUR FREIGHT SYSTEMS LLC | SCAC4 | ||
| 67 | BAAO | BROWN & ASSOCIATES INC | SCAC3 | ||
| 68 | BAAP | BARNDT, A PAUL | SCAC3 | ||
| 69 | BAAP | BAR RB LTD | SCAC4 | ||
| 70 | BAAQ | BARABOO ASPHALT COMPANY INC | SCAC3 | ||
| 71 | BAAQ | BREAK AWAY TRUCKING INC | SCAC4 | ||
| 72 | BAAS | BARAKAT ASSOCIATES LTD | SCAC3 | ||
| 73 | BAAS | BAR T5 AGRA SERVICES INC | SCAC4 | ||
| 74 | BAAU | BALTATLANTIC LINE | SCAC3 | ||
| 75 | BAAV | BAER, A VAN AND STORAGE INC | SCAC3 | ||
| 76 | BAAY | BASS, ANTHONY C | SCAC4 | ||
| 77 | BAB | Bahrain Air BSC (Closed) | ICAO1 | ||
| 78 | BABB | BASTANZIO, T INC | SCAC4 | ||
| 79 | BABC | BABCOCK, EARL S | SCAC3 | ||
| 80 | BABD | BALCH, BOB TRUCKING COMPANY | SCAC3 | ||
| 81 | BABE | BAILEY, ALBERT R | SCAC3 | ||
| 82 | BABF | B & B EXPRESS INC | SCAC3 | ||
| 83 | BABF | BAR K RANCHES | SCAC4 | ||
| 84 | BABH | B & B RIGGING & HAULING INC | SCAC3 | ||
| 85 | BABI | BABB TRUCKING CORP | SCAC3 | ||
| 86 | BABJ | B & B MOBILE HOME SALES INC | SCAC3 | ||
| 87 | BABJ | BARBA TIJERINA, MARTIN | SCAC4 | ||
| 88 | BABK | BASBCO TRUCKING INC | SCAC3 | ||
| 89 | BABM | B& B LINES, INC | SCAC3 | ||
| 90 | BABM | B & B LINES INC | SCAC4 | ||
| 91 | BABN | BABSON BROS TRUCKING CO | SCAC3 | ||
| 92 | BABO | BATTY BROS TRANSFER INC | SCAC3 | ||
| 93 | BABP | B & B TRANSPORTATION LIMOUSINE SERV | SCAC3 | ||
| 94 | BABQ | BAUER TRUCKING CO INC | SCAC3 | ||
| 95 | BABR | BARBOURSVILLE TRANSFER, INC | SCAC3 | ||
| 96 | BABS | BAB TRANSFER, INC | SCAC3 | ||
| 97 | BABS | BOARD AND BEAM | SCAC4 | ||
| 98 | BABU | BOYER ALASKA BARGE LINE, INC. | SCAC3 | ||
| 99 | BABU | BOYER LOGISTICS INC | SCAC4 | ||
| 100 | BABV | B & B TRANSFER & STORAGE CO | SCAC3 |