4,000 Horsepower -- Built 1989-1990 by GE - Erie, Pennsylvania
Existing Roster
| 8501 | 8502 | 8503 | 8504 | 8505 | 8506 | 8507 | 8508 | 8509 | 8510 |
| 8511 | 8512 | 8513 | 8514 | 8515 | 8516 | 8517 | 8518 | 8519 | 8520 |
| 8521 | 8522 | 8523 | 8524 | 8525 | 8526 | 8527 | 8528 | 8529 | 8530 |
| 8531 | 8532 | 8533 | 8534 | 8535 | 8536 | 8537 | 8538 | 8539 | 8540 |
| 8541 | 8542 |
Union Pacific's C40-8 Renumbering Plan
| CNW No. | UP No. | CNW No. | UP No. | |
| 8501 | 9023 | 8522 | 9044 | |
| 8502 | 9024 | 8523 | 9042 | |
| 8503 | 9025 | 8524 | 9046 | |
| 8504 | 9035 | 8525 | 9045 | |
| 8505 | 9027 | 8526 | 9047 | |
| 8506 | 9028 | 8527 | 9049 | |
| 8507 | 9029 | 8528 | 9050 | |
| 8508 | 9030 | 8529 | 9051 | |
| 8509 | 9031 | 8530 | 9052 | |
| 8510 | 9032 | 8531 | 9053 | |
| 8511 | 9033 | 8532 | 9054 | |
| 8512 | 9039 | 8533 | 9055 | |
| 8513 | 9034 | 8534 | 9056 | |
| 8514 | 9026 | 8535 | 9057 | |
| 8515 | 9037 | 8536 | 9058 | |
| 8516 | 9038 | 8537 | 9059 | |
| 8517 | 9048 | 8538 | 9060 | |
| 8518 | 9040 | 8539 | 9061 | |
| 8519 | 9041 | 8540 | 9062 | |
| 8520 | 9036 | 8541 | 9063 | |
| 8521 | 9043 | 8542 | 9064 |