Last revised: September 8, 2024
By: Adam Burns
The 2-8-8-2 was a Mallet-type steam locomotive used extensively by the Denver and Rio Grande Western. The numbers 2-8-8-2 refer to the wheel arrangement, which included two leading wheels, eight driving wheels, another set of eight driving wheels, and two trailing wheels.
This type of engine was most often operated in heavy drag service - and was particularly effective in mountainous terrain - where its high tractive effort and drawbar horsepower was well-suited in such environments. It was a perfect fit in the Rio Grande's rugged territory where main line grades commonly reached between 2-3%.
The 2-8-8-2s, which the railroad would eventually roster in four different classes, served it well for more than four decades. The final examples were not retired until the 1950s.
The Denver & Rio Grande Western Railroad (D&RGW) was renowned for its 2-8-8-2 Mallet steam engines. This distinctive class was the epitome of power, efficiency, and innovation in the world of steam locomotives during the 20th century.
In his book, "Rio Grande Railroad," author James Griffin notes the story of these impressive engines begins with the company's efforts to improve operational efficiency along the stiff grades of its main line over Tennessee Pass (Colorado) and Soldier Summit (Utah).
As trains became increasingly heavier the railroad needed to eliminate double-heading and acquired eight early 2-6-6-2s in 1909. Four years later, in 1913, the company picked up sixteen even more powerful 2-8-8-2s from Alco's Schenectady Works.
According to the railroad they hoped these new behemoths could replace two Consolidations in helper service, thereby lowering operational costs.
Moving onto specifics, the Rio Grande's 2-8-8-2s were characterized predominantly by two features: articulated construction and locomotive power.
The articulated construction was based on Anatole Mallet's design. The Mallet was essentially two engines housed under one frame whereby the rear set of drivers - or "engine" - was fixed on a rigid frame while the lead set swiveled to negotiate curves.
The advantage, of course, was greater levels of adhesion and horsepower. The Mallet was a compound articulated design; the high pressure steam was fed into the rear set of cylinders while the "spent" lead set captured the "wasted" low-pressure steam.
This cooler, lower-pressure steam required larger cylinders to maintain the same power, which gave the locomotives a somewhat cartoonish appearance. For its time, the Mallet offered improved efficiency and greater power, requiring less fuel and roughly half the water of a traditional engine.
Many railroads, particularly in mountainous regions, found the Mallet very beneficial in heavy drag service. In terms of power, the 2-8-8-2s were in a league of their own. Fueled by coal, their boiler was enormous and the fireboxes sufficiently large to generate high levels of steam pressure.
The initial L-95's (sometimes referenced as L-96) provided tractive efforts of over 95,000 pounds with the total engine and tender weight topping out at 605,000 pounds.
They earned their impressive reputations primarily due to their unmatched ability for effective mountaineering while hauling heavy freights. While the engines could be unstable at higher speeds they were predominantely only utilized in slow drag service on the Rio Grande.
As the Rio Grande's fortunes improved through the 1920s the railroad continue to acquire additional 2-8-8-2 designs; in 1923 it picked up ten Class L-107 compounds from Alco's Richmond Works and followed with ten more from Alco's Brooks Works in 1927, listed as Class L-131.
Mr. Griffin goes on to point out that the 131's, at the time of their delivery, were the most powerful steam locomotives in the world, offering tractive efforts of 131,000 pounds.
The 131's were also the Rio Grande's first to use simple steam expansion as the railroad moved on from the more complex - and maintenance intensive - compound Mallet designs.
It final batch, listed as Class L-132, came in 1930 from Schenectady. Interestingly, it is said the Rio Grande's classified these big articulateds by their peak tractive effort rating.
In an odd twist, perhaps as a means of differientiating the two groups, since the tractive efforts were in the 131,000 range, the Rio Grande rounded down with its first group (L-131) but rounded up with the second (L-132).
The big 2-8-8-2s tended to operate where the railroad needed them most, on the stiff grades of Soldier Summit and Tennessee Pass. When originally delivered the L-95s worked the Salt Lake Division - where grade's on Soldier Summit reached as high as 3.97%.
All of the big engines could also be found out on the main line, generally in service on Tennessee Pass. Interestingly, the big steamers were not generally well-liked by crews. They tended to be heavy smokers, which made breathing extremely difficult in the tunnels. Nevertheless, most remained in service beyond World War II.
Unfortunately, none of these impressive machines survived the scrappers torch. They tended to enter retirement in order of acquistion.
The Rio Grande's 2-8-8-2s, with their compelling mix of power, innovation, and challenges, embody a significant chapter in the history of American railroads.
From their service to their eventual retirement, they serve as robust symbols of the grit and determination it took to conquer the mountainous western American landscapes, transforming them into the heartland of a pioneering nation.
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