Big Boy #4014 Makes Slow U-Turn

Big Boy #4014 makes use of its articulated design across the diamond!

Big Boy #4014 was designed as an articulated locomotive for tight curves. The U-turn shown here pushes the limits on how tight the curve can be without slipping off of the rails.

Big Boy has a compounding of the steam meaning the steam is used once on both sets of driving wheels front and back. The articulated locomotive has the front boiler sitting on a front pilot wheeled truck that allows the otherwise ridged boiler to pivot around curves that would normally be too tight.

Since the Big Boys were built 132 feet long and weighed 1.2 million pounds each, the hinged design allowed them the flexibility to negotiate the curves.

Some Union Pacific Big Boy stats:

1. Operated from 1941-59
2. Bearing full load weighed a total of 1.2 million pounds
3. Only 25 ever made
4. 4-8-8-4 configuration
5. Top speed of 80 Mph

Let us know if you have had the opportunity to view Big Boy up close. We would love to hear about your experience!