| 3901 | WRPI | Western Railroad Properties | | | RSRV |
| 3902 | WRPN | WISE TRANSPORTATION, INC | | | SCAC1 |
| 3903 | WRPT | WALTER PRODUCTS INC | | | SCAC4 |
| 3904 | WRPX | Warr-Penn Refining Co. | 7/1930-7/1932 | | NAKINA |
| 3905 | WRPX | Public Service Co. of Indiana, Inc. | added 10/1978; 1/1980; eliminated 1/1991 | | NAKINA |
| 3906 | WRPX | PSI Energy, Inc. | added 1/1991; 1/1994; eliminated 10/1998; 7/2000 (not listed); added 10/2000; eliminated 1/2001; 7/2005 (not listed) | | NAKINA |
| 3907 | WRPX | Public Service Co. of Indiana, Inc. | added 10/78; 1/80; eliminated 1/91 | | NRHS |
| 3908 | WRPX | PSI Energy, Inc. | added 1/91; 1/94; eliminated 10/98; 7/2000; added 10/2000; eliminated 1/2001 | | NRHS |
| 3909 | WRPX | *WARR-PENN REFINING CO. | | | PWRC |
| 3910 | WRPX | *(PSIX) PSI ENERGY, INC. (PUBLIC SERVICE CO. OF INDIANA) | | | PWRC |
| 3911 | WRPX | Warr-Penn Refining (Public Service of Indiana) | | | RSRV |
| 3912 | WRQT | W R T | | | SCAC4 |
| 3913 | WRR | WRA, Inc. | Callsign: Wrap Air, | USA | AVCODES |
| 3914 | WRR | WRA Inc | | | ICAO1 |
| 3915 | WRR | Western Railroad Company | Real: WRRC | USA | TRAFFIC |
| 3916 | WRRC | Western Rail Road Co. | added 1/1976; 1/1980-7/2005 | | NAKINA |
| 3917 | WRRC | Western Rail Road Co. | 1/80-7/2000 | | NRHS |
| 3918 | WRRC | WESTERN RAIL ROAD CO. | | | PWRC |
| 3919 | WRRC | Western Railroad | | | RSRV |
| 3920 | WRRC | WESTERN RAILROAD COMPANY | | | SCAC4 |
| 3921 | WRRE | WARRIOR ENERGY | | | SCAC4 |
| 3922 | WRRG | WARD RUGH INC | | | SCAC4 |
| 3923 | WRRI | WERNER LLC | | | SCAC4 |
| 3924 | WRRL | WARRACK BROS TRUCKING LTD | | | SCAC4 |
| 3925 | WRRS | WORLD RESOURCE RECOVERY SYSTEMS INC | | | SCAC4 |
| 3926 | WRRT | WARREN TRANSPORT INC | | | SCAC4 |
| 3927 | WRRX | Walden's Ridge R.R. Co. | added 1/2004; eliminated 7/2004; 7/2005 (not listed) | | NAKINA |
| 3928 | WRRX | *SOUTHEASTERN INTERNATIONAL RAILROAD | | | PWRC |
| 3929 | WRRX | +WALDEN'S RIDGE RAILROAD CO. | | | PWRC |
| 3930 | WRRX | WALDENS RIDGE RAILROAD COMPANY INC | | | SCAC4 |
| 3931 | WRS | Western Rail Switching Inc. | 7/2005 | | NAKINA |
| 3932 | WRS | WESTERN RAIL SWITCHING INC. | | | PWRC |
| 3933 | WRS | WESTERN RAIL SWITCHING INC | | | SCAC4 |
| 3934 | WRS | Westdeutsche Rail Service GmbH | | DE | VKM |
| 3935 | WRSA | WORLDWIDE RELOCATION SPECIALISTSINC | | | SCAC4 |
| 3936 | WRSC | WESTERN RESOURCES INC | | | SCAC4 |
| 3937 | WRSCH | WRS Widmer Rail Services Personal AG | | CH | TRAFFIC |
| 3938 | WRSCH | WRS Widmer Rail Services Personal AG | | CH | VKM |
| 3939 | WRSE | WILD ROSE TRANSPORTATION SERVICES | | | SCAC4 |
| 3940 | WRSF | WESTERN REFINERY SERVICES INC | | | SCAC4 |
| 3941 | WRSH | Wrexham & Shropshire | | GB | TRAFFIC |
| 3942 | WRSK | WIERSEMA TRUCKING CORPORATION | | | SCAC4 |
| 3943 | WRSQ | WORLDWIDE RELOCATION SERVICES INC | | | SCAC4 |
| 3944 | WRSSK | Wagon Rail Service, s.r.o. | | SK | VKM |
| 3945 | WRSV | WALD RELOCATION SERVICES LTD | | | SCAC4 |
| 3946 | WRSW | WRS ENVIRONMENTAL | | | SCAC4 |
| 3947 | WRSX | Wheeler, Reynolds & Stauffer | 7/1937-4/1961; eliminated 1/1962 | | NAKINA |
| 3948 | WRSX | Stauffer Chemical Co. (Western Branch) | added 1/1962; eliminated 1/1963 | | NAKINA |
| 3949 | WRSX | Scholle Corp. | added 4/1973; 1/1975-1/1980; eliminated 4/1989 | | NAKINA |
| 3950 | WRSX | Warren Railcar Service, Inc. | 7/2000-7/2005 (not listed) | | NAKINA |
| 3951 | WRSX | Wheeler, Reynolds & Stauffer | 4/38-4/61; eliminated 1/62 | | NRHS |
| 3952 | WRSX | Stauffer Chemical Co. (Western Branch) | added 1/62 | | NRHS |
| 3953 | WRSX | Scholle Corp. | added 4/73; 1/75-1/80; eliminated 4/89 | | NRHS |
| 3954 | WRSX | Warren Railcar Service, Inc. | Jul-00 | | NRHS |
| 3955 | WRSX | *STAUFFER CHEMICAL CO. [WHEELER, REYNOLDS & STAUFFER] | | | PWRC |
| 3956 | WRSX | *SCHOLLE CORP. | | | PWRC |
| 3957 | WRSX | *WHITE RIVER SCENIC RAILROAD | | | PWRC |
| 3958 | WRSX | +WARREN RAILCAR SERVICE, INC. | | | PWRC |
| 3959 | WRSX | Wheeler, Reynolds & Stauffer (Scholle Corp) | | | RSRV |
| 3960 | WRSX | WARREN RAILCAR SERVICE, INC. | | | SCAC4 |
| 3961 | WRT | Wright Air Lines, Inc. | Callsign: Wright-Air, Founded in 1966. Merged with Aeromech Airlines in 1983. Ceased operations in 1985. | USA | AVCODES |
| 3962 | WRT | Wright Air Lines | | | ICAO1 |
| 3963 | WRT | Warrior River Terminal Co. | 1/1941-7/1954 | | NAKINA |
| 3964 | WRT | Warrior River Terminal Co. | Jan-52 | | NRHS |
| 3965 | WRT | WARRIOR RIVER TERMINAL CO. | | | PWRC |
| 3966 | WRTA | WESTERN RAILROAD ASSOCIATION | | | PWRC |
| 3967 | WRTA | WARRIOR TRANSPORT LLC, THE | | | SCAC4 |
| 3968 | WRTC | WHERTEC INC | | | SCAC4 |
| 3969 | WRTD | WATFORD ROOF TRUSS LTD | | | SCAC4 |
| 3970 | WRTE | WALRATH, T E TRUCKING INC | | | SCAC4 |
| 3971 | WRTF | WOLF, RICHARD TRUCKING INC | | | SCAC4 |
| 3972 | WRTG | WRAY TRUCKING CO LLC | | | SCAC4 |
| 3973 | WRTH | WANDA RUTH TRANSPORTATION | | | SCAC4 |
| 3974 | WRTI | WERNER TRANSPORTATION SERVICES INC | | | SCAC4 |
| 3975 | WRTK | WOLFE, RICHARD TRUCKING INC | | | SCAC4 |
| 3976 | WRTL | WILSON RAPID TRANSIT LINES, INC | | | SCAC1 |
| 3977 | WRTL | WILSON RAPID TRANSIT LINES INC | | | SCAC4 |
| 3978 | WRTM | WALTERS TRUCKING | | | SCAC4 |
| 3979 | WRTN | WARRIOR TRANSPORT INC | | | SCAC4 |
| 3980 | WRTP | WARD, ROGER TRANSPORTATION INC | | | SCAC4 |
| 3981 | WRTS | WARREN, W W TRANSFER & STORAGE CO | | | SCAC4 |
| 3982 | WRTV | WAGNER, ROB TRUCKING | | | SCAC4 |
| 3983 | WRTW | WARD, ROGER TRANSPORTATION INC (AUS | | | SCAC4 |
| 3984 | WRTX | Western Rail Leasing Corp. | added 7/1978; 1/1980; eliminated 10/1990 | | NAKINA |
| 3985 | WRTX | Western Rail Leasing Corp. | added 7/78; 1/80; eliminated 10/90 | | NRHS |
| 3986 | WRTX | RETIRED 902-10-92 ATP [WESTERN RAIL LEASING CORP.] | | | PWRC |
| 3987 | WRTX | Western Rail Leasing Corporation | | | RSRV |
| 3988 | WRTX | WISCONSIN RAILWAY PRESERVATION TRUS | | | SCAC4 |
| 3989 | WRTY | WRTS | | | SCAC4 |
| 3990 | WRTZ | WARREN TRUCK | | | PWRC |
| 3991 | WRUF | WOODRUFF ENTERPRISES | | | SCAC4 |
| 3992 | WRUS | WEISS-ROHLIG USA LLC | | | SCAC4 |
| 3993 | WRVC | WESTERN RV COUNTRY LTD | | | SCAC4 |
| 3994 | WRVI | WILKINS RECREATIONAL VEHICLES INC | | | SCAC4 |
| 3995 | WRVL | WHITERIVER LOGISTICS INC | | | SCAC4 |
| 3996 | WRVR | WILD RIVERS FARM | | | SCAC4 |
| 3997 | WRWK | Warwick Ry. Co. | added 1/1974; 1/1975-1/1980; eliminated 1/1983 | | NAKINA |
| 3998 | WRWK | Providence and Worcester R.R. Co. | added 1/1983; 1/1994-7/2005 | | NAKINA |
| 3999 | WRWK | Warwick Ry. Co. | added 1/74; 1/75-1/80; eliminated 1/83 | | NRHS |
| 4000 | WRWK | Providence and Worcester R.R. Co. | added 1/83; 1/94-7/2000 | | NRHS |
