SD50
Chris Carangi photo
The SD50, along with the GP50, was EMD's last major North American offering using the venerable 645 series diesel engine. Utilizing a larger turbocharger (originally tested on the SD45X) and a maximum RPM increase from 900 to 950, the SD50 produced 3500 horsepower. The SD50 had many teething problems early on, causing EMD's reputation to suffer and as a result. It is during this period that General Electric ousted EMD for the largest share of the domestic locomotive market, partly also due to GE's business practices, such as comprehensive maintenance contracts. While many of the early onset issues with the 50 series were eventually ironed out, later attempts to uprate the 645F3B to 3600 horsepower in mid-1985 led to further mechanical issues. Discovery of the 645F3B's limitations led EMD to develop the 710 series engine, a staple of EMD locomotives late 1986 onward.
A CN SD50F poses in Alorton, IL in 2007. In less than 2 years, this locomotive would be razor blades. Photo credit Keith B.
In 1985, Canadian National purchased 60 SD50-type locomotives with cowl styling on them. These locomotives, referred to as SD50Fs, were mechanically identical to their normal hood styling, however they were equipped with cowling to keep crews from walking out on icy, snow covered walkways in harsh Canadian winters. Only 7 survive in 2019 (With 5 in North Dakota and 2 in Montana), while the other 53 were scrapped around 2008-2009
| General Info | - |
|---|---|
| Prime Mover | EMD 16-645F3B |
| Horsepower | 3500 (1) |
| Truck Type | EMD HTC (2) |
| Axles | 6 |
| Traction Motors | 6 |
| Minimum Weight | 368000 lbs |
| Maximum Weight | 420000 lbs ⚠ |
| Model Base Speed | 70 MPH |
| Electrical System | - |
|---|---|
| Generator Max Current | 9900 Amps |
| Max Traction Motor (TM) Current | 1650 Amps |
| Max Continuous TM Current | 1170 Amps |
| Traction Motor Type | DC |
| Factor of Adhesion | 27% |
| Transition Mode | Automatic, no selector |
| Transition Groups | 1 |
| Transition Shunts | 1 |
| Generator Transition | Yes |
| Traction Control | APR + Sand |
| Dynamic Braking (DB) Mode (if used) | Mechanical Blowers |
| DB Max Current | 760 Amps |
| DB Max Continuous Current | 760 Amps |
| Blended Braking | No |
| Miscellaneous | - |
|---|---|
| Head-End Power (HEP) | No |
| HEP Power Consumption | N/A |
| HEP Standby/Run Mode | N/A |
| Load Ramp Speed | 2 Amps/Tick |
| TM Overload Protection | No |
| Starter Mode | Manual Primer, Manual Start |
| Air Brake Schedule | 26-L |
| Compressor CFM | 269.2 (WBO @ 954 RPM) |
| Main Reservoir Volume | 35 Cubic Feet |
⚠: Not Verified or Educated Guess
(1): 50 series locomotives built after mid-1985 were rated at 3600 horsepower.
(2): Conrail's early/mid SD50s came on EMD Flexicoil C trucks which had an adhesion rating of 25%.