| 1 | SSIX | The Standard Silicate Co. | 7/1930-7/1932 | | NAKINA |
| 2 | SSIX | Standard Silicate Co. (General American Tank Car Corp.) | added 11/1934; 7/1935 | | NAKINA |
| 3 | SSIX | SSI Rail Corp. | added 4/1977; eliminated 1/1978 | | NAKINA |
| 4 | SSIX | Itel Corp., Rail Division | added 1/1978; 1/1980; eliminated 4/1987 | | NAKINA |
| 5 | SSIX | Itel Rail Corp. | added 4/1987; eliminated 10/1992 | | NAKINA |
| 6 | SSIX | General Electric Railcar Services Corp. | added 10/1992; 1/1994; eliminated 1/2000 | | NAKINA |
| 7 | SSIX | General Electric Rail Services Corp. | added 1/2000; 7/2000-7/2005 | | NAKINA |
| 8 | SSIX | SSI Rail Corp. | eliminated 1/78 | | NRHS |
| 9 | SSIX | Itel Corp., Rail Division | added 1/78; 1/80; eliminated 4/87 | | NRHS |
| 10 | SSIX | Itel Rail Corp. | added 4/87; eliminated 10/92 | | NRHS |
| 11 | SSIX | General Electric Railcar Services Corp. | added 10/92; 1/94; eliminated 1/2000 | | NRHS |
| 12 | SSIX | General Electric Rail Services Corp. | added 1/2000; 7/2000 | | NRHS |
| 13 | SSIX | *STANDARD SILICATE CO. | | | PWRC |
| 14 | SSIX | +(NATX) (GENERAL ELECTRIC RAIL SERVICES CORP. [ITEL RAIL CORP.; SSI RAIL CORP.] | | | PWRC |
| 15 | SSIX | *SOUTH EAST SHORELINE, INC. | | | PWRC |
| 16 | SSIX | Itel Corporation | | | RSRV |
| 17 | SSIX | GENERAL ELECTRIC RAILCAR SERVICES C | | | SCAC4 |