The area around New Orleans is typically soft and spongy. When the New Orleans Great Northern needed a locomotive that was larger and faster than their 2-8-2s, it chose a light Mountain type. Normally, the purpose of the four-wheel leading truck of a locomotive is to assist in smooth running at speed. However, in the case of the New Orleans Great Northern, the purpose was to simply spread out the weight of the locomotive. At 273,000 lbs, the New Orleans Great Northern Mountains were one of the lightest of the type.

In 1929 the Gulf, Mobile & Ohio acquired the New Orleans Great Northern.