| 1 | IOX | Transit Co., Ltd. | added 10/1957; 10/1957-1/1975; eliminated 10/1975; 1/1980 | | NAKINA |
| 2 | IOX | Union Tank Car Co. | added 10/1953; 7/1954; eliminated 10/1957 | | NAKINA |
| 3 | IOX | Transit Co., Ltd. | 1/1952; eliminated 10/1953 | | NAKINA |
| 4 | IOX | Imperial Oil, Ltd. | 8/1920-1/1950 | | NAKINA |
| 5 | IOX | Imperial Oil, Ltd. | Apr-38 | | NRHS |
| 6 | IOX | Transit Co., Ltd. | 1/52; eliminated 10/53 | | NRHS |
| 7 | IOX | Union Tank Car Co. | added 10/53; eliminated 10/57 | | NRHS |
| 8 | IOX | Transit Co., Ltd. | added 10/57; 10/57-1/80 | | NRHS |
| 9 | IOX | *IMPERIAL OIL, LTD. | | | PWRC |
| 10 | IOX | *UNION TANK CAR CO. (TRANSIT CO., LTD.) | | | PWRC |
| 11 | IOXP | INTEROCEAN EXPRESS CORPORATION | | | SCAC4 |
