Greatest Steam Locomotive Ever Built

This is the Union Pacific "Big Boy" No. 4005, on public display at the Forney Museum in Denver, Colorado. No. 4005 is probably the most historic Big Boy because it was converted to burn oil. It was later converted back to burn coal, when the oil burning experiment didn't work as well as hoped. A Big Boy is 85 feet 9 1/2 inches long without its coal tender, and 132 feet 9 7/8 inches with tender. To give you an idea of the scale of this photograph, I am 6'1" tall. The top of my head is almost even with the top of a Big Boy 68" drive wheel (the larger wheels). The additional wheel height is due the tracks and ties. Click here to see a size comparison.

It should be noted here that the Big Boys were not the heaviest and most powerful steam locomotives built. That honor goes to the Allegheny type locomotives operated by the Chesapeake & Ohio Railroad. The Big Boys were by far the more popular of the two locomotive types.

The Big Boy, and probably other steam locomotives, sported some special markings on the cab. Click here for explanation of those markings.