1980 heavy switcher renumberings: SP 2961-2970, 3102-3105, 3106-3109

These units were renumbered from SD35 and SD35E units as heavy switchers in 1980.
1980 NUMBERS:
Englewood Yard Hump units: SP 2961-2970:
| 1980 road number | 1974 road number | orig road number |
| SP 2961 | SP 4700 | SP 4816 |
| SP 2962 | SP 4701 | SP 4822 |
| SP 2963 | SP 4702 | SP 4834 |
| SP 2964 | SP 4703 | SP 4839 |
| SP 2965 | SP 4704 | SP 4829 |
| SP 2966 | SP 4705 | SP 4821 |
| SP 2967 | SP 4706 | SP 4841 |
| SP 2968 | SP 4707 | SP 4842 |
| SP 2969 | SP 4708 | SP 4823 |
| SP 2970 | SP 4709 | SP 4819 |
SD35E Heavy Switchers: SP 3102-3105:
| 1980 road number | GRIP number | orig road number |
| SP 3102 | SP 6950 | SP 4838 |
| SP 3103 | SP 6951 | SP 4828 |
| SP 3104 | SP 6952 | SP 4818 |
| SP 3105 | SP 6953 | SP 4830 |
SD35 Heavy Switchers: SP 3106-3109:
| 1980 road number | 1965 number | orig road number |
| SP 3106 | SP 6919 | SP 4835 |
| SP 3107 | SP 6924 | SP 4840 |
| SP 3108 | SP 6927 | SP 4843 |
| SP 3109 | SP 6928 | SP 4844 |