SDP40F - MagnumMacKivler/RLCPT2 GitHub Wiki
A pair of SDP40Fs lead Amtrak’s Empire Builder in June of 1974 at Cut Bank, Montana. Photo credit Dick Kuelbs
The SDP40F was a passenger locomotive built for Amtrak, and was the first power purchased by the newly formed government passenger entity. With cowling based off of the Santa Fe's FP45, the SDP40F utilized an SD40-2 frame and trucks, and could easily be converted over into a freight unit (also like the FP45) incase the fledgling passenger provider Amtrak failed. The SDP40F also had a steam generator for steam-heated cars of the time, and was geared higher than the SD40-2 to reach speeds of 94 MPH (sometimes even 100 MPH).
Unfortunately, with high speeds, water tanks that were mounted towards the rear of the locomotive, and lighter, hollow baggage carts behind the locomotive, the SDP40Fs had a major tendency to rock back and forth on the tracks at higher speeds. While it was never pinpointed what caused it, this rocking motion on the locomotives had serious consequences on the locomotives, and caused major derailments, especially throughout curves.
These derailments caused many railroads to ban the SDP40Fs on their tracks, and in 1977 the Federal Railroad imposed a nationwide speed restriction of 40 mph through curves of 2 degrees or more for the locomotives. Conrail even went a step further, and did not purchase the HTC truck on any of their new locomotives (though the trucks were never pinpointed as a major cause), and opted instead for the older Flexicoil C truck on orders of SD40, SD40-2, and as late as SD50 locomotive models.
Amtrak 632, a victim of harmonic vibrations notorious on these units, sits off the Seaboard tracks in Safety Harbor, Florida on February of 1976. This derailment likely prompted Seaboard to reject all future Amtrak trains with SDP40Fs on them. Photo credit Mike Robbins.
Eventually, the newer Amtrak F40PH came along when most steam heated cars were either retrofitted with the electric "Head End Power" system, or were retired from the Amtrak roster. Amtrak eventually returned some SDP40F locomotives to EMD to have their components used in new F40PHs to receive a discount, or sold the remaining SDP40Fs to the ATSF railroad (who already had passenger-turned-freight FP45s and freight only F45 locomotives with the cowling) to be used on freight trains in exchange for Santa Fe's homemade switching locomotive rebuilds (like the CF-7). These new found freight locomotives had steam generators removed, notches cut into their noses for crews to ride in while switching, and split water/fuel tanks converted over to fuel only; on ATSF, they were reclassified as the SDF40-2
A former ATSF, now BNSF, SDF40-2 sits in a special Maersk Container Lines paint scheme for a the 2002 grand opening of BNSF's Arsenal Yard in Joliet, Illinois. This was the only SDF40-2, and one of only 2 SDP40Fs as of 2019 to survive. (The other one is EMD 169 that does testing work on the FRA's Pueblo, Colorado research facility; it currently is not preserved.) This locomotive is now a part of the Dynamic Rail Preservation group, and is on display in Boulder City, Nevada.
In total, 150 SDP40F locomotives were produced between June of 1973 and August of 1974. All were produced for Amtrak
PT-Specific Information
| General Info | - |
|---|---|
| Prime Mover | EMD 16-645E3C |
| Horsepower | 3000 |
| Truck Type | EMD HTC |
| Axles | 6 |
| Traction Motors | 6 |
| Minimum Weight | 360000 lbs ⚠ |
| Maximum Weight | 387000 lbs ⚠ |
| Model Base Speed | 65 MPH |
| Top Speed | 65, 71, 77, 83, 89, or 95 MPH |
| Electrical System | - |
|---|---|
| Generator Max Current | 6000 Amps |
| Max Traction Motor (TM) Current | 1500 Amps |
| Max Continuous TM Current | 1050 Amps |
| Traction Motor Type | DC |
| Factor of Adhesion | 27% |
| Transition Mode | Automatic, no selector |
| Transition Groups | 2, 1, 1 ⚠ |
| Transition Shunts | 1, 1, 0.5 ⚠ |
| Generator Transition | No |
| Traction Control | APR + Sand |
| Dynamic Braking (DB) Mode (if used) | Mechanical Blowers |
| DB Max Current | 700 Amps |
| DB Max Continuous Current | 700 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 | 255.1 (WBO @ 904 RPM) |
| Main Reservoir Volume | 35 Cubic Feet |
Notes
⚠: Not Verified or Educated Guess