What is a ‘Big Boy’?

What is a ‘Big Boy’?

By Roger Heid


Someone who knows I am dabbling with railroads asked me what a Big Boy is. I knew he wasn’t talking about some Hamburger Joint. I am aware that a lot of you know what I am talking about. For those of you, who do not know, let me inform you.

The ‘Big Boy’ was the largest steam engine that ever saw production and extensive use.

Produced between 1941 and 1944, it was operated by Union Pacific until 1959, mostly out of their Wyoming Division. It was the only locomotive to implement a 4-8-8-4 wheel configuration. Viewed from the side, it looks like this:  oo OOOO OOOO oo


There is a 4-wheel leading truck to provide stability, a 4-wheel trailer truck to provide support for the rather large firebox. The 8-axle drive wheels are subdivided into two individual trucks to facilitate curves in the track. This is referred to as ‘Articulation’. Hence, the drive wheels are articulated. Many other large steam engines feature this articulation.

It is said that some worker in the manufacturer’s plant (ALC  -  American Locomotive Company) scribbled the words ‘Big Boy’ on it, using a piece of chalk. This stuck, and that is how this engine got its name.

In my collection you will find a sample, made by Maerklin. It came in a nice wooden box. It also contains a piece of rail for presentation purposes. It was securely bolted to the bottom of the box to prevent shipping damage.


It works rather well, even in a tight curve radius. It has all the whistles and bells. In order to be able to use all of its digital features, you need to have the Maerklin Control Station 60215.

Sporadically, over the years, Maerklin has offered this locomotive for a given year, or so. It always seems to depend on public demand. If there is enough demand, they will re-introduce it.

Currently, Maerklin offers a weathered rendition of it. (#37995). For the 2-rail DC folks, Rivarossi has one in store for you. For the Z-scalers amongst you, AZL has one of them. Just look those up in the REI (Reynaulds) web site.

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