The Union Pacific 4015 Big Boy 4-8-8-4
Trix model 22599
Review by Neil Wood
10 minute stop to cool the train's wheels
after the long braking descent
from the top of the Wasatch grade. William *****, 1942.
Central to Union Pacifics network is
the steep line between Cheyenne and Laramie which traverses the Wasatch
Rocky Mountains. At the end of the 1930s freight trains on this route became
longer, faster and required time-consuming, costly double heading with
several locomotives. Union Pacific required a single locomotive
capable of pulling 3,600 tons of train unassisted over the 1.14% grade of
the Wasatch route.
A tractive effort of 135,000 lbs would be
needed to pull 3,600 tons. With an axle loading of 67,500lbs each,
this required 8 drivers or a 4-8-8-4 wheel arrangement. The result was
considered by many to be the most successful articulated steam locomotive
ever built. The first in the series of 25 was delivered to Omaha on
5/9/41. Built in two batches by Alco Locomotive works, the first batch
4000- 4019 was built in 1941 and the second 4020-4024 delivered in 1944.
The last revenue freight pulled by a Big
Boy was in July of 1959. Most were retired in 1961, although the last was
retired in 1962. The average mileage was around 1,000,000 miles.
While there are other locomotives which have exceeded the Big Boy in terms
of weight, length, horsepower, and tractive effort it is generally agreed
that this is the largest steam locomotive to run in regular service.
As this was the largest steam locomotive
in history it created the opportunity to make a superlative model.
This is an expensive model and stands at the top of the Trix HO price range.
This for Trix is no mean feat as their models are generally regarded as
expensive. Billed as the largest H0 steam locomotive ever built by
Trix this was one model I was waiting for with baited breath.
4015 under the coaling tower
Denver , 1954. Photo R. Kindig.
Specifications of the 4-8-8-4 Big Boy