The Yellowstone is an older class of locomotive. It was developed and designed by the Northern Pacific Railroad. I want to say around 1928 it appeared on the scene. Alco built the first one and hosted a dinner inside the fire box boasting the largest fire box of any locomotive. It was made to burn Rosebud coal. A type of coal that was almost like just plain dirt. At this time the Northern Pacific Z-5 Yellowstone was THE largest locomotive ever built.
People said in Livingston that when this engine came into town, the ground shook and basically everyone stopped what they were doing to see this intimidating-thundering beast through the yard. This must have been something.
The EM-1 - shares the same wheel arrangement of a yellowstone but really is not a Yellowstone. Its drivers, smoke box, tender, cab, boiler size, fire box, are totally unique.The DMIR Yellowstone is a closer copy.
Its sort of like saying the AC-9 was a Yellowstone... no not really. It just had a similar wheel arrangement.
The Big Boy on the other hand really belongs in it own class. Its more of a super steam engine / modern design of an engine. It was developed and designed and the first engine was released in 1941, almost 18 years after the first Yellowstone. As a matter a fact the Z-5 Yellowstone was pretty much used as a helper at that point on Bozeman pass in Montana. It could not keep up with the higher speeds of the Challenger Z-6.
For reading/photos that you really may enjoy:
The Northern Pacific Railway of McGee and Nixon: Classic Photographs of Equipment and Environment During the 1930-1955
Amazing photos from two incredible gentleman. I believe Mr. McGee still is alive and well and lives in Livingston, Montana.
