EMD SD45X
An EMD SD45X is a 6-axle experimental road switcher diesel-electric locomotive built by General Motors Electro-Motive Division between June 1970 and February 1971. Power was provided by an EMD 645E3A 20-cylinder engine which generated. 7 examples of this locomotive model were built for American railroads. 6 of these units would end up in service with Southern Pacific Railroad. One was rebuilt in 1980 by Morrison-Knudsen into an with a long hood from a scrapped DD35.
| Qty. | Railroad | Road Numbers | Date | Builders #s | Notes |
| 1 | EMD | 4201 | 6/70 | 36806 | EMD demo, to SP 9503, 12/72 |
| 2 | EMD | 4202, 4203 | 2/71 | 36807, 36808 | EMD demo, to SP 9504-9505, 12/72 |
| 1 | EMD | 5740 | 6/70 | 34123 | |
| 1 | Southern Pacific | 9500 | 8/70 | 35741 | |
| 2 | Southern Pacific | 9501, 9502 | 9/70 | 35742, 35743 |