SD7 - MagnumMacKivler/RLCPT2 GitHub Wiki
A CB&Q SD7, still with classic "SD7" indication plates on its battery box, sits at Clyde, Illinois on March 7, 1965. Photo credit to Chuck Zeiler
The SD7 was the first 6 axle EMD road switcher offered, and thus helped to put the new "Special Duty" signature name in the spotlight of railroads for decades to come. Riding on newly designed Flexicoil C trucks, the SD7 took the same 567 engine block of the proven F7, and put it together into a new six axle designed hood unit that would be easier to see for road crews to use in either direction.
The EMD SD7 was made from May of 1951 to November of 1953 to then be replaced by the 1750 HP SD9. 188 units were made, with primary purchasers being Southern Pacific (43) and Chicago, Burlington, and Quincy (37) respectively.
PT-Specific Information
| General Info | - |
|---|---|
| Prime Mover | EMD 16-567B (1) |
| Horsepower | 1500 HP |
| Truck Type | EMD "Flexicoil" C |
| Axles | 6 |
| Traction Motors | 6 |
| Minimum Weight | 300,000 lbs |
| Maximum Weight | 360,000 lbs |
| Model Base Speed | 65 MPH |
| Top Speed | 55, 65, 71, 77, 83, or 89 MPH |
| Electrical System | - |
|---|---|
| Generator Max Current | 3000 |
| Max Traction Motor (TM) Current | 1500 |
| Max Continuous TM Current | 900 |
| Traction Motor Type | DC |
| Factor of Adhesion | 25% |
| Transition Mode | Automatic with Selector |
| Transition Groups | 3, 2, 2, 2 |
| Transition Shunts | 1, 1, 0.66, 0.33 |
| Generator Transition | No |
| Traction Control | APR with sanding |
| Dynamic Braking (DB) Mode (if used) | Mechanical Blowers |
| DB Max Current | 900 |
| DB Max Continuous Current | 700 |
| 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 | 24RL or 6BL |
| Compressor CFM | 216 CFM (WBO @ 800RPM) |
| Main Reservoir Volume | 28.9 Cubic Feet ⚠ |
###Notes:
(1) Later SD7 engines used the EMD 567C block, however they too produced 1500 horsepower.
⚠: Not verified or educated guess