The Athearn ATH73740 SD40 is a great HO scale model of the C&O Chesapeake & Ohio locomotive #7457 with DCC and sound. In 1966, EMD sent the first of five orders of SD40s to the C&O railroad. These were the most powerful units then, weighing 394,000 pounds each and having 82,100 lbs. of continuous tractive effort at 11.1 mph. Units 7450 - 7469, like this one, came in the '35 style' paint with yellow noses and small side initials. The SD40 got 3,000 hp from a turbocharged V16. Many were built for American, Canadian, and Mexican railroads. This model has lots of great features. It has LED lighting, photo - etched stainless steel windshield wipers, and separately applied wire grab irons. It also has a curved radiator fan grab iron, coupler cut levers, and rubber MU hoses. The sound - equipped models have an onboard DCC decoder with SoundTraxx Econami sound and a single cube speaker for good sound. They work in both DC and DCC, with some functions limited in DC.

Using your Athearn SD40 locomotive model is easy. First, make sure your track is clean and properly connected. Place the locomotive on the track. If you're using DC, you can start it up and control basic functions like forward and reverse. In DCC mode, you can access more features like different sounds and lighting effects. For the sound, just turn it on and enjoy the engine, horn, and bell sounds. When storing the model, keep it in the interior plastic blister to protect it. For maintenance, regularly clean the wheels with a soft cloth to ensure smooth operation. Check the electrical connections from time to time. If you want to change some functions, refer to the CV chart in the box. Just be careful when handling the model to avoid damaging the delicate parts like the wire grab irons and windshield wipers. Also, note that the minimum radius for the track is 18 inches, but a 22 - inch radius is recommended for better performance.