SP S4 page
The SP owned a total of 64 ALCO S4 switch engines. Fifty-four units for the SP and ten units for the T&NO were rostered.
The SP purchased S4's new as follows:
SP 1464-1485:
| Orig. road numbers | ALCO const. no. | build date |
| SP 1464-1470 | 79339-79345 | 11/1951 |
| SP 1471-1485 | 79503-79517 | 12/1951-1/1952 |
SP 1514-1528:
| SP 1514-1525 | 80092-80103 | 10/1952=4/1953 |
| SP 1525-1528 | 79815-79817 | 4/1953 |
SP 1551-1567:
| SP 1551-1557 | 81129-81135 | 3-4/1955 |
| SP 1558-1567 | 81310-81319 | 3-4/1955 |
T&NO 95-104:
| Orig. road numbers | ALCO const. no. | build date |
| T&NO 95-99 | 79220-79224 | 10/1951 |
| T&NO 100-104 | 79334-79338 | 11/1951 |