Athearn HO Scale SD40 Review

C&O SD40
Athearn's new Ready to Roll SD40 features many improvements over previous models. C&O versions include distinctive details like the rounded rock plow and hood-mounted bell. ©2015 Ryan C Kunkle, licensed to, Inc.

Athearn's latest SD40 brings many improvements over previous models, including those by Athearn themselves. The new models feature a newly tooled body and the option for DCC and sound at low cost. 

Owned by many railroads, the SD40 should find a home on just about any layout set in the 1960s or later. This new release offers an inexpensive way to add a quality model to your layout, expand your roster, or as a launching pad for more detailed models.


Each road name is available in up to four numbers and with or without sound and DCC. Sound versions retail for $184.98 and non-equipped for $134.98.

Prototype History

EMD's SD40 ranks as one of the most popular and enduring locomotives of the late 20th Century. Introduced as a mid-horsepower option in 1963, the SD40 would prove to be more efficient and reliable than the highly touted and more powerful SD45.

Production reached 1,268 units by 1972 when the model was replaced by the upgraded SD40-2. Over the nine years of its production, there were many variations in the details of the SD40 including customer specified options.

The majority of SD40s built are still on the rails today. Most remaining units have been rebuilt to SD40-2 standards. For many of these rebuilding projects there was little change in the exterior of the locomotive. Through sale and merger, these units have worked for far more than there initial owners and have worn many paint schemes.

Model Details

Athearn released its first SD40 models in its ready-to-roll line more than ten years ago after acquiring the body from Rail Power Products. The models were good runners but the body tooling lagged behind what is available today.

This new release features many improvements in overall dimensions and details.

A more modular construction has also allowed for increased fidelity to the prototype with changes like correct traction motor blower duct styles for just one example.

Each paint scheme offered includes many details specific to that road. In many cases, there are detail differences between the different road numbers offered in each scheme. The Southern Pacific units offer perhaps the most extensive array of these detail changes so far. These units represent the railroad's rebuilt models and include such unique details as the style of cab windows and even different fan styles on the roof.

While some modelers will undoubtedly want to add more details, these stock models already feature more details than were previously offered as "standard" on ready-to-roll series models such as plows, MU hoses, coupler cut levers, radio antennae and more.

Value Sound

The big news about these new locomotives on their release wasn't the improved tooling but the economy sound. The DCC / Sound equipped versions include Soundtraxx Tsunami sound-economy decoders. These decoders don't feature all the "bells and whistles" of a full sound decoder, but they do give you all of the options that most modelers will ever use - maybe even a few more.

To my ears, these decoders capture the sounds of the SD40's prime mover beautifully. Bell and horn are crisp, though the horn is a little soft in comparison to the bell. These individual sounds should be able to be adjusted by programming cv's.

My only complaint about the DCC and sound is that no manual is provided for the decoder. In fact, there is not even a mention of the decoder in what is otherwise a very nice parts diagram and list. To get the appropriate manuals and quick-start guide, there is a link to Soundtraxx manuals in pdf format on the Athearn website under the "More" drop down menu.


The locomotive performs very much like other previously reviewed Athearn Ready-to-Roll models. The motor and gearboxes run very quietly and smoothly without binding. Slow speed performance is very good.


While the locomotive and decoder will work on conventional dc layouts, sound controls will be more limited and the locomotive requires a very high starting voltage. It will work better with other sound-equipped locomotives but will not run at comparable speeds with standard engines.

The only performance issue of note is that, as is the norm for Athearn, the locomotives feature light bulbs instead of LEDs. While converting an Athearn to LED lights is not a difficult project, these models would be much nicer if they came so equipped. Locomotives do feature working extra warning or gyrolights as appropriate by roadname. These lights only work in DCC versions and are not wired in DCC-ready models

Paint and Finish

I've purchased multiple locomotives for this review. Each of the paint schemes shows sharp deco work. The colors and lettering are accurate and legible down to the smallest print. Aside from adding a little weathering to suit, there is little most modelers will want to do to enhance the finish on these models.

Overall, these models are nice additions to Athearn's line and will be to your roster. While the locomotives overall measure up nicely with what we've come to expect from an industry leader, the low cost of the DCC and sound addition is a big deal.

At $50 difference in list price, many who may not have considered DCC or sound before may be more open to the idea. Once you've tried it, you'll never want to run any other way. For those who've already made the conversion, the low cost is a welcome change from the trends in rising prices and a great value overall.


Manufacturer's Site