DM&IR was pleased with the first batch (class M-3) of 8 received from Baldwin in 1941 so they ordered 10 duplicates (class M-4). They were completed late in 1943 after much of DM&IR's traffic had subsided, so some of the M-4s were leased by and delivered directly to the Denver & Rio Grande Western. The following winter the D&RGW again borrowed the 2-8-8-4s for use as helpers over the 10,239-foot Tennessee Pass crossing of the continental Divide. The D&RGW sent a telegram to the DM&IR stating that the Yellowstones were the finest steam locomotives to ever operate on its road.
On the DM&IR they were used as the main road power to pull ore trains throughout the Duluth area. For the most part, ore trains had to be pulled downhill to the ore docks on Lake Superior in Duluth and Two Harbors. These trips did not require the enormous pulling force of the Yellowstones. Surprisingly, the limiting factor (as far as what the iron range locomotives could pull) was the 2.2 percent grade from Duluth up to the yards in Proctor. The ore cars had to be returned empty to these yards for sorting.
The Yellowstones were sometimes used to pull empties up this hill from Duluth to Proctor. However, the classic 'hill' power was the older modified 2-8-8-2 'Hill' engines with their extra air tanks on top of the boiler. Newer 2-10-4s and 0-10-2s were also used on the 'Hill' at least in the mid-late 50's when steam was still on the line. Someone once told me that he spoke to a couple people (including the diesel shop foreman who used to fire the Yellowstones and a former engineer on the Yellowstones) at the Proctor roundhouse while 227 was being restored in preparation for its display in the museum in Duluth. They said that it was possible to empty the tender of almost all coal and water of a Yellowstone while pulling a load of empty ore cars up the hill from Duluth to Proctor. This is to say: 25,000 gallons water and 25-26 tons of coal! This is hard to believe and perhaps it is a bit of an exaggeration, but it does show that this was one of the more difficult tasks for the Yellowstones.
All of the DM&IR Yellowstones were all retired between 1958 and 1963 except for 237 which was sold for scrap after a wreck. Fortunately, three survive today.
These classic engines were based to a large extent on the Western Pacific's M-137-151 2-8-8-2 engines of 1931 (Locobase 332), but were lengthened to take an all-weather cab . The DM & IR engines burned bituminous coal and had a smaller grate area than the oil-burning M-137s although the overall firebox heating surface grew by 11 sq ft (1 sq m). In the M-4, this total included 194 sq ft (18 sq m) in three thermic syphons, 177 sq ft (16.45 sq m) in the combustion chamber, and 32 sq ft (3 sq m) of arch tubes. As part of the M-137 revision, the combustion chamber's length grew from 6 to 7 feet (2,134 mm).
Boiler tube and flue length (sheet to sheet) was shortened by 2 feet to 21 feet (6.4 m). The mixture of tubes and flues changed as the design substituted a Type E superheater for the M-137's Type A. The number of 2 1/4-in flues decreased to 82 and Baldwin installed 245 of the 3 3/4-in flues (vs. the M-137's 270 of the former and 75 5 1/2-in flues) . As a result, superheater area increased by 25%. The first five M-4s had Worthington feedwater heaters, the last five Elescos. Four piston valves each measured 12" (306 mm) in diameter.
Following contemporary practice, the M-3s had integrally cast frames and cylinders, Timken roller bearings on all driving axles, ASF (M-3) or SKF (M-4) roller bearings on all truck axles.
These engines performed very well from the time they entered service in May 1941, soon handling train loads 25% heavier than the earlier M-1/M-2 engines could manage. The last ten engines were M-4s, built by Baldwin in 1943, which used carbon steel in certain components because of a shortage of high-tech alloy steels. They had an engine weight of 699,700 lb (317,379 kg).
During 1943-44, as many as 12 "Yellowstones" were operating on the D & RGW, the GN, and the NP under lease where they were highly regarded. In fact, the D & RGW telegraphed the DM&IR with the claim that these Yellowstones were the finest engines ever to run on the Rio Grande.
The Lake Superior Railroad Museum site -- http://www.lsrm.org/Museum/mallet.htm (visited 9 Feb 2004) -- gives some interesting consumption numbers: " When working at full power, [the locomotive] could consume some 10 to 12 tons of coal an hour and evaporate water into steam at the astounding rate of 12,000 gallons per hour. The amount of coal ...used in one hour would be enough to heat a home for two winters." (and Minnesota winters at that, one supposes.)
|Principal Dimensions by Steve Llanso of Sweat House Media|
|Railroad||Duluth, Missabe & Iron Range (DM&IR)|
|Number in Class||18|
|Locomotive Length and Weight|
|Driver Wheelbase (ft / m)||17.25 / 5.26|
|Engine Wheelbase (ft / m)||67.17 / 20.47|
|Ratio of driving wheelbase to overall engine wheebase||0.26|
|Overall Wheelbase (engine & tender) (ft / m)||113.49 / 34.59|
|Axle Loading (Maximum Weight per Axle) (lbs / kg)|
|Weight on Drivers (lbs / kg)||560,257 / 254,129|
|Engine Weight (lbs / kg)||695,040 / 315,265|
|Tender Loaded Weight (lbs / kg)||438,000 / 198,674|
|Total Engine and Tender Weight (lbs / kg)||1,133,040 / 513,939|
|Tender Water Capacity (gals / ML)||25,000 / 94.70|
|Tender Fuel Capacity (oil/coal) (gals/tons / ML/MT)||26 / 23.60|
|Minimum weight of rail (calculated) (lb/yd / kg/m)||117 / 58.50|
|Geometry Relating to Tractive Effort|
|Driver Diameter (in / mm)||63 / 1600|
|Boiler Pressure (psi / kPa)||240 / 16.50|
|High Pressure Cylinders (dia x stroke) (in / mm)||26" x 32" / 660x813 (4)|
|Tractive Effort (lbs / kg)||140,093 / 63545.19|
|Factor of Adhesion (Weight on Drivers/Tractive Effort)||4.00|
|Firebox Area (sq ft / m2)||750 / 69.70|
|Grate Area (sq ft / m2)||125 / 11.62|
|Evaporative Heating Surface (sq ft / m2)||6782 / 630.30|
|Superheating Surface (sq ft / m2)||2770 / 257.43|
|Combined Heating Surface (sq ft / m2)||9552 / 887.73|
|Evaporative Heating Surface/Cylinder Volume||172.45|
|Computations Relating to Power Output (More Information)|
|Robert LeMassena's Power Computation||30,000|
|Same as above plus superheater percentage||38,700|
|Same as above but substitute firebox area for grate area||232,200|
|DM&IR 225 in Proctor, MN. 2009 photo by Wes Barris|
|DM&IR 227 in Duluth, MN. Photo by John L Blamey|
|DM&IR 221 in Two Harbors, MN. Photo by Annabelle Gallagher|
|DM&IR 229 in Two Harbors, MN. 1992 photo by Wes Barris|
Details provided by Al Mamer