Therefore I say it was and is the largest steam engine that was ever created... There was a machine called the Allegheny type which I think was a 4-6-6-6 which some believe was actually more powerfull and heavier than the Big Boy.
Its girth requires a 4-8-8-4 wheel configuration to keep it rock-steady on the rails. With a puny 7,000 horsepower, Big Boys had a maximum tractive power of 135,375 pounds, all to pull huge loads of freight across steep grades in Utah's Wasatch Mountains and the Rockies.
Does Russia still use steam locomotives? No. The last one was manufactured in 1953. They've been replaced by other types of locomotives with efficiency rates higher than 13%.
With regular maintenance, British steam locomotives typically lasted for approximately 30 years of intensive use, before major components would need to be replaced or overhauled. For a steam locomotive built in 1960, the economic lifespan would have led to it being withdrawn in the 1990s.
The class J-1 and J-3a Hudsons of 1927 had 79 inch drivers. They were fast, powerful, very well proportioned, good looking, and may have been the best known steam locomotive. Honorable Mentions: CMStP&P Class F7.
The Big Boys were built for power. They did the work of three smaller engines, pulling 120-car, 3800 ton freight trains at forty miles per hour in the mountains of Utah and Wyoming. With power, though, comes weight - larger cylinders, pistons, drive rods, boiler and firebox.
Jim Wrinn was quoted in USA Today as estimating the cost to restore the 4014 at roughly $4 million. If I remember correctly, Stephen Lee was the engineer on the 844 trip.
If the diesel engine referenced is the modern diesel electric locomotive that has been accompanying 4014 in its travels, my understanding is that Union Pacific utilizes it to assist with overall fuel efficiency and to provide regenerative braking. This helps with operating costs and provides a better level of safety.
The Big Boy No. 4014 steam locomotive rolled out of a Union Pacific restoration shop in Cheyenne for a big debut after five years of restoration. It then headed toward Utah as part of a yearlong tour to commemorate the Transcontinental Railroad's 150th anniversary.
All of the Big Boys were coal-burning, stoker-fired, designed to run 7,000 horsepower at 70 miles per hour. They have been lauded in the industry as the highest horsepower, heaviest, and longest steam locomotives ever built.
Union Pacific No.4014 is a Big Boy class steam locomotive having a 4-8-8-4 wheel arrangement. They are the heaviest single expansion steam locomotive ever built, weighing about 1,200,000 pounds.
The Centennials were the largest diesel-electric locomotives ever built. Actually comprising two engines on one frame, they delivered 6,600 horsepower. Designed and built exclusively for Union Pacific Railroad, the units were named in honor of the railroad's centennial anniversary celebration in 1969.