Athearn G71128 HO EMD SD75M Santa Fe ATSF 220

Continuing upon the successful SD60-series, in 1992 EMD debuted the next step in locomotive evolution with the SD70-series. While outwardly similar at first glance to the SD60M, the D.C.-drive SD70M featured several external design refinements from the predecessor model. Battery boxes were relocated to the left-hand side walkway immediately behind the cab, a large, boxy forward traction motor blower housing replaced the angular version used on SD60s, the raised walkway duct on the left hand walkway was eliminated, and an intake for the rear traction motor blower on the left hand side of the carbody, directly under the rear radiator intake grill, was added.

Internally, the SD70 boasted improvements as well; a 16-710GB prime mover, rated at 4,000hp, was coupled to a new alternator design, the AR20. New D70TR traction motors were standard, and controlling all of this power and locomotive function was EMD’s new EM2000 microprocessor, which boasted more memory, twice the processing speed, and improved locomotive self-diagnostic capabilities compared to the processor suite used in the SD60. Even more revolutionary was the inclusion of EMD’s patented “Radial” truck design, the HTC-R. This design, which made its debut under EMD Demo SD60 #3, replaced the venerable HT-C truck, and is unique in its ability to shift, or “steer”, the wheelsets laterally through curves, resulting in greatly reduced wheelset and track wear, and coupled with the new D70TR traction motors and EM2000 microprocessor, greatly improved adhesion.

Continuing with previous practice, EMD built a set of Demonstrator SD70Ms, EMD 7000-7002, all equipped with the North American safety-cab (hence the “M” in their model designation), and decked out in an attractive gray, silver, and burgundy paint scheme. These units traveled all over North America, showing off the latest technology from EMD. Atchison Topeka and Santa Fe railroad requested a 4300 horsepower version resulting in the SD75M. As production continued, EMD incorporated their new “Whisper Cab” design resulting in the SD75I. The updated cab SD75I was purchased by Santa Fe successor Burlington Northern and Santa Fe, Canadian National, and the Ontario Northland.

Santa Fe’s last official EMD order before the BNSF merger, was for 51 SD75M’s placed in 1994. The SD75M differs from the SD70M by a slight horsepower increase (4300 vs 4000), and an extra equipment bulge along the engineer’s side of the body. They were delivered in Santa Fe’s “Superfleet” scheme that was re-introduced in the late 1980’s/Early 1990’s.

FEATURES:

As-delivered appearance
Small EMD plow
Round deck mounted front ditch lights
Large Sinclair antenna
Early EMD trucks with hidden bearings
Coupler cut levers
Flexible Trainline and MU hoses
MU stands
Windshield wipers
Lift rings
Wire grab irons
Walkway tread
Sanding lines
Lit signal lights and/or beacons, if equipped
Detailed fuel tank with fuel fillers, fuel gauges, and breather pipes
Speed recorder unless noted
EMD HTCR trucks, early with hidden bearings, or late with exposed bearings per prototype
See-through cab windows and full cab interior
Fine-scale Celcon handrails for scale appearance
Body-mounted McHenry® scale knuckle couplers – Kadee® compatible
DCC-ready features Quick Plug™ plug-and-play technology with 21-pin NEM connector
Scaled from prototype resources including drawings, field measurements, photographs, and more
Accurately painted and printed paint schemes
Genesis driveline with 5-pole skew wound motor, precision machined flywheels, and multi-link drivetrain
All-wheel drive with precision gears for smooth & quiet operation
All-wheel electrical pickup provides reliable current flow
Wheels with RP25 contours operate on all popular brands of track
LED lighting for realistic appearance
Heavy die-cast frame for greater traction and more pulling power
Packaging securely holds for the model for safe storage
Minimum radius: 18” — Recommended radius: 22”