Subscriber & Member Login

Login, or register today to interact in our online community, comment on articles, receive our newsletter, manage your account online and more!

Athearn HO scale SD70ACe with Tsunami2

Read this review from the February 2019 Model Railroader
Athearn HO scale SD70ACe with Tsunami2
A skew-wound motor with brass flywheels is secured to the center of the die-cast metal frame. Plastic driveshafts power all 12 wheels, which also pick up current.

In 1943, employees of the Union Pacific RR agreed to an extra deduction in their paychecks to buy War Bonds during World War II. The railroad collected $379,000 for the cause, and in response, the U.S. Army Air Corps named a B-17 bomber “Spirit of the Union Pacific.”

In 2017, Union Pacific unveiled SD70ACe no. 1943, The Spirit, as part of a Salute the Military Tour. Athearn has now released an HO scale Genesis series model decorated in The Spirit’s unique paint scheme, and equipped with a SoundTraxx Tsunami2 dual-mode decoder as an option.

The prototype. Originally built as UP no. 9046 and designated SD70AH by the railroad, the Electro-Motive Diesel locomotive is a 4,300-hp unit with alternating-current traction motors. It’s the last model to feature EMD’s two-stroke diesel engine, in this case a 16-710G3C-2.

Built from 2004 to 2014, 13 railroads purchased SD70ACes new, including 518 for UP. Between 2014 and 2016, Union Pacific received an additional 273 units designated SD70AH, for “heavy.” These engines carry extra ballast to increase their weight to 428,000 pounds, 8,000 more than a standard unit.

Locomotive no. 1943 is the 16th Union Pacific commemorative unit in the railroad’s history. The paint scheme on The Spirit starts with a cab and nose in silver, honoring the Air Force. The blue sash with the “Spirit of the Union Pacific” lettering copied from the B-17 recalls the Strategic Air Command sash formerly painted on SAC aircraft.

The Coast Guard’s racing stripe separates the Air Force silver from Navy battleship gray, which is the background for Union Pacific’s American flag. This is followed by a camouflage pattern to honor the Army and Marines. The rear of the locomotive features the POW-MIA flag with the lettering “You are not forgotten.”

The model. Much of the current release is the same as the model reviewed in the February 2011 Model Railroader. The notable changes include the optional SoundTraxx Tsunami2 dual-mode decoder, and a switch to light-emitting diodes (LEDs) for illumination.

The most obvious difference on this highly detailed Genesis series model is the paint scheme. Athearn is proud of the effort put in to replicate the complex Union Pacific design, as well it should be. The paint is smooth and opaque with clear separations between the different sections, including the green, brown, and tan camo pattern as it crosses doors, radiator fans, brake wheel, and other details.

Many details are etched-metal parts, including most of the grills. The combined dynamic brake and traction motor intake grill is especially well done, with the silhouette of the Chicago Blower cooling fan visible inside.

The cab roof is held on with magnets, allowing access to add crew members. In addition to the engineer’s control console and three crew seats, there’s an event recorder in the left-hand windshield and cabinet doors and panels on the cab’s rear wall.

On the test track. I wanted to hear the SoundTraxx Tsunami2 decoder, so I went right to Digital Command Control (DCC) testing. Using our NCE PowerCab system, I recorded a starting speed of 4.1 scale mph in speed step 1, and a top speed of 77 scale mph in speed step 28. Switching to 128 speed steps, the locomotive crawled along at 1.1 scale mph in speed step 1. Drawbar pull measured just over 3 ounces, equivalent to 43 HO scale freight cars.

After the test track, I took the locomotive to our staff layout, the Milwaukee, Racine & Troy. There, I followed the instructions in the included user manual to set up the Dynamic Digital Exhaust.

With that done, I enabled the Tsunami2 braking rates following those instructions. Where SoundTraxx instructs you to set configuration variable (CV) 1.403, that means you first set CV32 to 1, then change CV 403. I also changed the values for baseline acceleration rate, CV3, and baseline deceleration rate, CV4. This simulates the momentum of the 214-ton machine. A quick change to the long address to match the cab number and the programming was done.

The addition of momentum and braking programming made the locomotive much more satisfying to run. The Spirit responded like a powerful, heavy road unit. Setting the Dynamic Digital Exhaust meant the sound of the diesel engine rose and fell as the apparent (and physical) load on the engine changed.

I was also able to consist the locomotive with an older Athearn Genesis SD70ACe equipped with an original Tsunami decoder with no problems.

I also tested the locomotive in direct-current (DC). At 7V, the start-up sounds commenced. The locomotive started to move at 9.75V at 2.5 scale mph. Speed at 12V was 25 scale mph, and the top voltage our DC power pack provided, 14V, translated to 42 scale mph. While that’s lower than the prototype’s top speed, it seemed reasonably fast for a model railroad.

Sound in DC was limited to engine revs rising and falling with locomotive speed, and the sound of brakes squealing as I brought the locomotive to a stop.

In the Spirit. With its flashy paint scheme and patriotic theme, this modern locomotive makes an eye-catching addition to any layout. And if you’re looking for a paint scheme more appropriate for another part of the country, Athearn has several other road name options equipped similarly to our test model.

Whether you choose to model UP territory, or somewhere farther east, you won’t go wrong with this locomotive.

Price (Spirit of Union Pacific no. 1943): $339.98 (Digital Command Control and sound), $249.98 (direct current)
Price (other roadnames): $309.98 (Digital Command Control and sound), $219.98 (direct-current)
Athearn Trains
1600 Forbes Way, Suite 120
Long Beach, CA 90810
Era: 2017 to present, based on paint scheme
Road names (multiple road numbers):
Union Pacific “Spirit of the Union Pacific,” CSX, Electro-Motive Division leasing, Ferromex, Norfolk Southern/Reading heritage, Norfolk Southern/Virginian heritage, PRLX, Union Pacific
Correctly sized operating ditch lights
Factory-installed wire grab irons
HTCR or HTSC trucks per prototype
Light-emitting diode (LED) lighting
McHenry scale couplers, mounted at correct height
Weight: 1 pound, .6 ounce

Join the discussion

Read and share your comments on this article
Comment on this article
Want to leave a comment?
Only registered members of are allowed to comment on this article. Registration is FREE and only takes a couple minutes.

Login or Register now.


Add more operational possibilities to your layout.

Model Railroader Newsletter See all
Sign up for our FREE e-newsletter and get model railroad news in your inbox!
By signing up you may also receive occasional reader surveys and special offers from Model Railroader magazine. Please view our privacy policy