| Number | Class | Built | Retired | Notes |
|---|---|---|---|---|
| 270:1 | GY-00a | 1978 | HBU-4 hump booster unit (slug), renumbered to 510 in 1990 | |
| 270:2 | GY-00m | 1991 | Jan 5 2007 | converted from S-3 switcher 701 usually operated with GP9 72xx series mother |
| 271:1 | GY-00a | 1978 | HBU-4 hump booster unit (slug), renumbered to 511 in 1990 | |
| 271:2 | GY-00m | 1993 | Converted by AMF Technotransport from GP9 4462 usually operates with GP9 72xx series mother | |
| 272:1 | GY-00a | 1978 | Renumbered to 512 in 1990 | |
| 272:2 | GY-00g | 19932011 | Converted by AMF Technotransport from GP9 4212 usually operates with GP9 72xx series mother. scrapped in September 2013 | |
| 273:1 | GY-00a | 1978 | Renumbered to 513 in 1990 | |
| 273:2 | GY-00g | 1993 | Converted by AMF Technotransport from GP9 4595 usually operates with GP9 72xx series mother | |
| 274:1 | GY-00a | 1978 | Renumbered to 514 in 1990 | |
| 274:2 | GY-00g | 1993 | Converted by AMF Technotransport from GP9 4422 usually operates with GP9 72xx series mother | |
| 275:1 | GY-00a | 1978 | Renumbered to 515 in 1990 | |
| 275:2 | GY-00g | 1993 | Converted by AMF Technotransport from GP9 4393 usually operates with GP9 72xx series mother damaged while leading GP9 CN 7275, early October 2004; struck tank truck near Cecile Junction QC; repaired | |
| 276:1 | GY-00a | 1978 | Renumbered to 516 in 1990 | |
| 276:2 | GY-00g | 1993 | GP9 slug, converted by AMF Technotransport from GP9 4585 usually operates with GP9 72xx series mother | |
| 277:1 | GY-00a | 1978 | HBU-4 hump booster unit (slug),renumbered to 517 in 1990 | |
| 277:2 | GY-00g | 1993 | GP9 slug, converted by AMF Technotransport from GP9 4459 in 1993 second use of this number as a slug usually operates with GP9 72xx series mother | |
| 278:1 | GY-00a | HBU-4 hump booster unit (slug),built new 1978 renumbered to 518 in 1990 | ||
| 278:2 | GY-00g | 1993 | GP9 slug, converted by AMF Technotransport from GP9 4520 usually operates with GP9 72xx series mother | |
| 279:1 | GY-00a | 1978 | HBU-4 hump booster unit (slug), renumbered to 519 in 1990 | |
| 279:2 | GY-00g | 1993 | GP9 slug,converted by AMF Technotransport from GP9 4452 usually operates with GP9 72xx series mother | |
| 280:1 | GY-00a | 1978 | HBU-4 hump booster unit (slug), renumbered to 520 in 1990 | |
| 280:2 | GY-00g | 1994 | GP9 slug,converted by AMF Technotransport from GP9 4466 in 1994 second use of this number as a slug usually operates with GP9 72xx series mother | |
| 281:1 | GY-00a | 1978 | HBU-4 hump booster unit (slug) renumbered to 521 in 1990 | |
| 281:2 | GY-00g | 1993 | GP9 slug,converted by AMF Technotransport from GP9 4470 usually operates with GP9 72xx series mother | |
| 282 | GY-00a | 1978 | HBU-4 hump booster unit (slug), renumbered to 522 in 1990 |
