SD70MAC - MagnumMacKivler/RLCPT2 GitHub Wiki
A Burlington Northern SD70MAC shows off the executive scheme, exclusive to only SD70MAC locomotives and the railroad executive train F9 and E9 streamlined units. Photo credit unknown
The SD70MAC was Electro-Motive's answer to the newly created General Electric AC4400CW, and featured the Siemens 1TB2630 AC traction motor (also used in the SD60MAC). Alternating current locomotives are able to haul heavy trains at lower speeds a lot more effectively than traditional direct current locomotives, and most railroads purchased them for unit train service. The SD70MAC was the first introduction to AC locomotives for most railroads, and primarily railroads after their 70MAC orders purchased AC locomotives exclusively from both EMD and GE (with the exception of Canadian National and Norfolk Southern).
The SD70MAC was only available with the wide cab, however it still retained the "M" in the designation to signify its presence, as this was EMD's practice at the time. No standard cab "SD70AC" was ever made, nor cataloged.
Alaska Railroad purchased SD70MAC locomotives for not only coal service, but also had a small order set up for passenger service as well. This batch of locomotives was equipped with Head End Power for modern electricity setup by using power from the traction motors. Electro-motive Division, however, did not officially offer this, and this was a setup created for the special needs of the ARR
The SD70MAC was produced from 1993 to the end of 2004, when the EPA Tier 2 diesel emissions requirements took effect. The replacement to this locomotive was the Tier-II compliant SD70ACe. The total number of units was 1109 locomotives.
PT-Specific Information
| General Info | - |
|---|---|
| Prime Mover | EMD 16-710G3B, G3C |
| Horsepower | 4000 (1) |
| Truck Type | EMD HTCR |
| Axles | 6 |
| Traction Motors | 6 |
| Minimum Weight | 410,000 lbs ⚠ |
| Maximum Weight | 430,000 lbs ⚠ |
| Model Base Speed | 74 MPH |
| Top Speed | 74, 80, 86, and 92 MPH ⚠ |
| Electrical System | - |
|---|---|
| Generator Max Current | 4530 Amps (4) |
| Max Traction Motor (TM) Current | 755 Amps (4) |
| Max Continuous TM Current | 755 Amps (4) |
| Traction Motor Type | AC |
| Factor of Adhesion | 35% |
| Transition Mode | Automatic, no Selector |
| Transition Groups | 1 |
| Transition Shunts | 1 |
| Generator Transition | No |
| Traction Control | ETC |
| Dynamic Braking (DB) Mode | Electrical Blowers |
| DB Max Current | 755 Amps ⚠ |
| DB Max Continuous Current | 755 Amps ⚠ |
| Blended Braking | No |
| Miscellaneous | - |
|---|---|
| Head-End Power (HEP) | No (2) |
| HEP Power Consumption | N/A (2) |
| HEP Standby/Run Mode | N/A (2) |
| Load Ramp Speed | 1 Amps/Tick |
| TM Overload Protection | N/A |
| Starter Mode | Manual Primer, Manual Start (3) |
| Air Brake Schedule | 26L |
| Compressor CFM | 254 (Gardner Denver WBO @ 900 RPM) |
| Main Reservoir Volume | 33.8 Cubic Feet ⚠ |
###Notes:
⚠: Not verified or educated guess
(1) Later units were produced with 4300 Horsepower, though the change from the 710G3B to G3C occurred prior to the increase and does not denote this.
(2) Some Alaska Railroad SD70MACs were equipped with Head End Power. However, it was not a factory option from EMD. AS OF MAY 23, 2019, THE WAY THAT THESE LOCOMOTIVES PRODUCE HEP IS UNABLE TO BE REPLICATED WITH RLC PT
(3) Later locomotives were equipped with fully automatic starters.
(4) AC electrical gear is three-phase. Value shown here is for a single phase; the value used by RLC PT2 should be 3 times the value shown.