SD18 - MagnumMacKivler/RLCPT2 GitHub Wiki
A Chicago, Illinois and Midland SD18 sits in Springfield, Illinois. Photo credit to railarchive.net and David V. Leonard
The EMD SD18 was an improved offering of the popular SD9. This new locomotive took advantage of EMD's "Horsepower ratings" like their competitors (Such as the ALCo C420 with 2,000 HP or the GE U25B with 2,500 HP), which would be the standard until the GP30.
The SD18 was produced between April of 1960 to March of 1963, with only 104 examples being made; 60 of those were foreign units to Brazil and Korea, thus outnumbering their 54 American cousins. American railroads that purchases the SD18 included the DMIR (19), C&O (19), B&LE (7), and the C&IM (2).
The Chesapeake and Ohio Railroad (C&O) took advantage of a trade-in program that EMD had, and their order of SD18s rode on former 3 axle ALCo Tri-mount trucks.
A C&O SD18 with trucks from former ALCo trade-ins. Photo credit to Chessie Photo Archives and Dean J. Heacock
PT-Specific Information
| General Info | - |
|---|---|
| Prime Mover | EMD 16-567D1 |
| Horsepower | 1800 HP |
| Truck Type | EMD "Flexicoil" C (1) |
| Axles | 6 |
| Traction Motors | 6 |
| Minimum Weight | 328,000 lbs ⚠ |
| Maximum Weight | 390,000 lbs ⚠ |
| Model Base Speed | 65 MPH |
| Top Speed | 65, 71, 77, 83, or 89 MPH |
| Electrical System | - |
|---|---|
| Generator Max Current | 3000 |
| Max Traction Motor (TM) Current | 1500 |
| Max Continuous TM Current | 900 (1) |
| Traction Motor Type | DC |
| Factor of Adhesion | 25% |
| Transition Mode | Automatic with Selector |
| Transition Groups | 3, 2, 1, 1, 1 |
| Transition Shunts | 1, 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 | 700 |
| 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 | 26L (2) |
| Compressor CFM | 229.1 (WBO @ 835 RPM) |
| Main Reservoir Volume | 28.9 Cubic Feet ⚠ |
###Notes:
(1) Some SD18s rode on traded in ALCo Trimount trucks, including the ALCo 752 traction motors. Their factor of adhesion would still be 25%, however their Max continuous TM current would be 1085 Amps
(2) 24RL or 6BL braking systems were optionally offered
⚠: Not verified or educated guess