Trucks: B-B Zero Weight Transfer
Engine: 12-251-C3-V, 2,000 hp.
Gear ratio: 65:18
Maximum speed: 65 mph
Operating weight (lbs.): Nos. 2500 – 2529 262,000 lbs. ; Nos. 2530 – 2559 260,000 lbs.
Tractive effort (lbs.): 50,000
Length: 61′ – 0″
Order no: 4929 (Nos. 2500 – 2529), 4934 (Nos. 2530 – 2559)
Renumbered to 3500 number series in XXXX when the locomotives were lightened by reducing their fuel and sand capacities.
| Road no. | Class | Build date | Builder’s no. | Renumbered to | Date | Retired | Notes / disposition |
| 2500 | MR-20a | Jun 73 | M6071-01 | 3500 | |||
| 2501 | MR-20a | May 73 | M6071-02 | 3501 | |||
| 2502 | MR-20a | May 73 | M6071-03 | 3502 | |||
| 2503 | MR-20a | Jun 73 | M6071-04 | 3503 | |||
| 2504 | MR-20a | Jun 73 | M6071-05 | 3504 | |||
| 2505 | MR-20a | Jun 73 | M6071-06 | 3505 | |||
| 2506 | MR-20a | Jun 73 | M6071-07 | 3506 | |||
| 2507 | MR-20a | Jun 73 | M6071-08 | 3507 | |||
| 2508 | MR-20a | Jun 73 | M6071-09 | 3508 | |||
| 2509 | MR-20a | Jun 73 | M6071-10 | 3509 | |||
| 2510 | MR-20a | Jun 73 | M6071-11 | 3510 | |||
| 2511 | MR-20a | Jul 73 | M6071-12 | Feb 2 83 | Wrecked Sept 24 81 in a head on collision between trains #427 and #428 on Lac St. Jean Subdivision Seven locomotives were retired Nos. 2511, 2526, 2552, 3119, 3126, 3240 and 4488. Shipped to Moncton, NB on a flat car for scrapping. | ||
| 2512 | MR-20a | Jul 73 | M6071-13 | 3512 | |||
| 2513 | MR-20a | Jul 73 | M6071-14 | 3513 | |||
| 2514 | MR-20a | Jul 73 | M6071-15 | 3514 | |||
| 2515 | MR-20a | Jul 73 | M6071-16 | 3515 | |||
| 2516 | MR-20a | Jul 73 | M6071-17 | 3516 | |||
| 2517 | MR-20a | Aug 73 | M6071-18 | 3517 | |||
| 2518 | MR-20a | Aug 73 | M6071-19 | 3518 | |||
| 2519 | MR-20a | Aug 73 | M6071-20 | 3519 | |||
| 2520 | MR-20a | Aug 73 | M6071-21 | 3520 | |||
| 2521 | MR-20a | Oct 73 | M6071-22 | 3521 | |||
| 2522 | MR-20a | Sep 73 | M6071-23 | 3522 | |||
| 2523 | MR-20a | Sep 73 | M6071-24 | 3523 | |||
| 2524 | MR-20a | Sep 73 | M6071-25 | 3524 | |||
| 2525 | MR-20a | Sep 73 | M6071-26 | 3525 | |||
| 2526 | MR-20a | Sep 73 | M6071-27 | Feb 2 83 | Wrecked Sept 24 81 in a head on collision between trains #427 and #428 on Lac St. Jean Subdivision Seven locomotives were retired Nos. 2511, 2526, 2552, 3119, 3126, 3240 and 4488. Shipped to Moncton, NB on a flat car for scrapping. | ||
| 2527 | MR-20a | Sep 73 | M6071-28 | 3527 | |||
| 2528 | MR-20a | Sep 73 | M6071-29 | 3528 | |||
| 2529 | MR-20a | Sep 73 | M6071-30 | 3529 | |||
| 2530 | MR-20b | Mar 74 | M6081-01 | 3530 | |||
| 2531 | MR-20b | Apr 74 | M6081-02 | 3531 | |||
| 2532 | MR-20b | Apr 74 | M6081-03 | 3532 | |||
| 2533 | MR-20b | Apr 74 | M6081-04 | 3533 | |||
| 2534 | MR-20b | Apr 74 | M6081-05 | 3534 | |||
| 2535 | MR-20b | Apr 74 | M6081-06 | Feb 2 83 | Wrecked Sept 24 81 in a head on collision between trains #427 and #428 on Lac St. Jean Subdivision Seven locomotives were retired Nos. 2511, 2526, 2552, 3119, 3126, 3240 and 4488. Shipped to Moncton, NB on a flat car for scrapping. | ||
| 2536 | MR-20b | Apr 74 | M6081-07 | 3536 | |||
| 2537 | MR-20b | Apr 74 | M6081-08 | 3537 | |||
| 2538 | MR-20b | Apr 74 | M6081-09 | 3538 | |||
| 2539 | MR-20b | Apr 74 | M6081-10 | 3539 | |||
| 2540 | MR-20b | Apr 74 | M6081-11 | 3540 | |||
| 2541 | MR-20b | Apr 74 | M6081-12 | 3541 | |||
| 2542 | MR-20b | Apr 74 | M6081-13 | 3542 | |||
| 2543 | MR-20b | May 74 | M6081-14 | 3543 | |||
| 2544 | MR-20b | May 74 | M6081-15 | 3544 | |||
| 2545 | MR-20b | May 74 | M6081-16 | 3545 | |||
| 2546 | MR-20b | May 74 | M6081-17 | 3546 | |||
| 2547 | MR-20b | May 74 | M6081-18 | 3547 | |||
| 2548 | MR-20b | May 74 | M6081-19 | 3548 | |||
| 2549 | MR-20b | May 74 | M6081-20 | 3549 | |||
| 2550 | MR-20b | May 74 | M6081-21 | 3550 | |||
| 2551 | MR-20b | May 74 | M6081-22 | 3551 | |||
| 2552 | MR-20b | May 74 | M6081-23 | Dec 31 83 | |||
| 2553 | MR-20b | Jun 74 | M6081-24 | 3553 | |||
| 2554 | MR-20b | Jun 74 | M6081-25 | 3554 | |||
| 2555 | MR-20b | Jun 74 | M6081-26 | 3555 | |||
| 2556 | MR-20b | Jun 74 | M6081-27 | 3556 | |||
| 2557 | MR-20b | Jun 74 | M6081-28 | 3557 | |||
| 2558 | MR-20b | Jun 74 | M6081-29 | 3558 | |||
| 2559 | MR-20b | Jun 74 | M6081-30 | 3559 | |||
| 2560 | MR-20c | Nov 76 | M6092-01 | 3560 | |||
| 2561 | MR-20c | Nov 76 | M6092-02 | 3561 | |||
| 2562 | MR-20c | Nov 76 | M6092-03 | 3562 | |||
| 2563 | MR-20c | Nov 76 | M6092-04 | 3563 | |||
| 2564 | MR-20c | Nov 76 | M6092-05 | 3564 | |||
| 2565 | MR-20c | Nov 76 | M6092-06 | Nov 3 87 | Hit a log truck in Napadogan NB, Sep 20 86. | ||
| 2566 | MR-20c | Dec 76 | M6092-07 | 3566 | |||
| 2567 | MR-20c | Dec 76 | M6092-08 | 3567 | |||
| 2568 | MR-20c | Dec 76 | M6092-09 | 3568 | |||
| 2569 | MR-20c | Dec 76 | M6092-10 | 3569 | |||
| 2570 | MR-20c | Dec 76 | M6092-11 | 3570 | |||
| 2571 | MR-20c | Dec 76 | M6092-12 | 3571 | |||
| 2572 | MR-20c | Dec 76 | M6092-13 | 3572 | |||
| 2573 | MR-20c | Dec 76 | M6092-14 | 3573 | |||
| 2574 | MR-20c | Dec 76 | M6092-15 | 3574 | |||
| 2575 | MR-20c | Jan 77 | M6092-16 | 3575 | |||
| 2576 | MR-20c | Jan 77 | M6092-17 | 3576 | |||
| 2577 | MR-20c | Feb 77 | M6092-18 | 3577 | |||
| 2578 | MR-20c | Feb 77 | M6092-19 | 3578 | |||
| 2579 | MR-20c | Feb 77 | M6092-20 | Wrecked at mile 116 Joliette Subdivision in 1977, repaired and returned to service 1980. |