DDA40X - MagnumMacKivler/RLCPT2 GitHub Wiki
Two DDA40X locomotives, along with a GP20 B unit pull a hotshot trailer and container train in Sept. 1973. Photo credit Kevin Cavanaugh
The DDA40X was a dual engine locomotive exclusively made for Union Pacific by Electromotive Division. The Do-Do (4-4 wheeled), cab equipped (termed with an "A") 40 series (which meant it was equipped with a turbocharged V16 645E3 engine) e x perimental locomotive was made for UP between 1969 and 1971. The locomotive experimented with modular electronics that were later used in the "Dash 2" locomotive line (such as the SD38-2 and GP40-2), and also uniquely increased the horsepower to 3300 for each engine (not used for Dash 2 locomotives.)
These locomotives, made in time for the 100 year anniversary of the 1869 completion of the Transcontinental Railroad, were nicknamed "Centennials" among railfans.
47 examples were made; 34 were scrapped (some for their cabs by Morrison Knudsen passenger GP40 rebuilds), 11 were preserved in museums, and 1 is used as a parts locomotive for one more locomotive: UP 6939, the sole operating DDA40X locomotive in the world, for Union Pacific as a part of their heritage fleet.
PT-Specific Information
| General Info | - |
|---|---|
| Prime Mover | 2x EMD 16-645E3 |
| Horsepower | 6600 HP (1) |
| Truck Type | EMD "Flexicoil" D |
| Axles | 8 |
| Traction Motors | 8 |
| Minimum Weight | 519,000 lbs ⚠ |
| Maximum Weight | 563,000 lbs ⚠ |
| Model Base Speed | 65 MPH |
| Top Speed | 65, 70, 76, 82, or 90 MPH (1) |
| Electrical System | - |
|---|---|
| Generator Max Current | 6000 |
| Max Traction Motor (TM) Current | 1500 |
| Max Continuous TM Current | 1050 |
| Traction Motor Type | DC |
| Factor of Adhesion | 25% |
| Transition Mode | Automatic |
| Transition Groups | 1 |
| Transition Shunts | 1 |
| 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 |
| Compressor CFM | 254 (WBO @ 900 RPM) |
| Main Reservoir Volume | 33.8 Cubic Feet ⚠ |
###Notes:
(1): The first three units were delivered as 7000 horsepower, they were later derated to 6600 horsepower and all future units were built as such.
(2): Union Pacific DDA40X engines were geared for 90 MPH for faster trains.
⚠: Not verified or educated guess