www.rgusrail.com - DM&IR Yellowstones

The DM&IR Yellowstones were built in two classes, M3 and M4, by Baldwin in 1941 and 1943. There were 8 M3s (#220-227) and 10 M4s (#228-237). They took their name from the “Yellowstone Route”, the name for the Northern Pacific line, which first ordered the 4-8-8-2 type.

There are only 3 DM&IR Yellowstones remaining in the US, one at the Lake Superior Railroad Museum in downtown Duluth, MN, one on open air display about 8 miles west in Proctor, MN, and one on outdoor display at Two Harbors, MN, 27 miles from Duluth on the north shore of Lake Superior.

No NP Yellowstones have survived.

#227 is located at the Lake Superior Railroad Museum in Duluth. It was restored by DM&IR for the museum and is in really excellent condition. Because there is no natural light in the engine room, however, and the artificial lighting is quite low, it is not easy to get a good full-length shot of the locomotive.

Every 20 minutes when the museum is open (on the hour, 20 minutes past and 20 minutes to) the locomotive’s lights are switched on and the wheels turned automatically, which gives a good idea of how the gears of these massive engines worked.

The museum also has a model of M3 #225 sporting its original grey boiler jacket.

The model is on loan from the Ralph W. Andres Trust and has great detail.

The backhead of #227 shows a fearsomely complicated set of piping, gauges, handles, taps, levers and gears. The cab was over eleven feet across and ten feet deep, and was enclosed to protect the crew from harsh weather.

The Yellowstones were the first road locomotives purchased by the DM&IR in 18 years and were designed to handle the anticipated increased volumes of ore over the Iron Range division to Two Harbors with the build up of war traffic. Except for #237, which was damaged in a wreck on lease to the Denver & Rio Grande Western in 1958, they operated for about 20 years. Other than the three preserved locomotives, they were all retired between 1962 and 1963 and sold for scrap.

Although lighter in overall weight, the DM&IR Yellowstones were heavier on the drivers and had greater tractive force than either Big Boys or Alleghenies.

DMI&R Yellowstones did not have the largest grates (at 125 sq. ft. they were 30% smaller than NP Yellowstones) but superior bituminous coal shipped from the east and a slightly larger total evaporative area more than compensated. Boiler pressure was 240 psi.

Note to the two thermic siphons supporting the firebrick arch.

#229 is the only surviving M4. It went on display at Two Harbors next to the old DM&IR depot building (now home to the Lake County Historical Society) on 2nd June 1967. Sadly, the damp northern Minnesota weather is clearly hard on the locomotive.

Built in 1943, the M4s were identical in design to the M3s but were over 4.5 thousand pounds heavier because carbon steel was substituted for alloy on certain components as a result of shortages associated with the war effort. Unlike #225 and #227, #229 was fitted with a Worthington SA feedwater heater.

Because no ore was shipped out of the Mesabi or Vermillion in winter, many of the M4s were initially leased out to the Denver & Rio Grande Western, as well as to the Northern Pacific and the Great Northern.

The last Yellowstone steamed in 1962, and all remaining of the class were retired in 1963.

Prior to putting the new Yellowstones into service, DM&IR invested heavily in capital improvements, including new engine houses and turntables to accommodate the 128 foot locomotives, new tools and shop equipment and raised water standpipes to supply the 14 foot high tender manholes. 115 lb rail was also installed on the southbound track to Two Harbors and adjacent tracks were re-spaced on some curves to allow lateral clearance for the big boilers.

The DM&IR Yellowstones were fitted with Baker valve gear, the only application to the class. Drivers are 63” diameter and the cylinders are 26” in diameter with a 32” stroke. Note the Elesco Feedwater Heater in front of the smoke stack.

Although often referred to as Mallets, these were not. A true Mallet reuses steam from the first set of cylinders in larger, lower pressure cylinders (usually at the front of the locomotive), a process called compounding, which was developed by the Swiss engineer Anatole Mallet (1837-1919). After 1924, except for the Norfolk & Western, no more Mallet compounds were built for US railroads. Like the DM&IR Yellowstones, new four cylinder locomotives were built to supply steam directly to both sets of cylinders (called simple) and these should really be referred to just as articulateds. Many roads also converted their existing compounds to simple.

You can see an example of a N&W Y6a class Mallet on the St. Louis Transportation Museum page of this website.

#225 is on open display just off US Highway 2 in Proctor. It was donated to the city by DM&IR on 25th March 1963. Proctor has a long association with the company: there is a large marshalling yard just a half mile north of #225.

In 1995, the grey boiler jacket was removed, which made the locomotive less susceptible to water penetration and deterioration. When I visited in September 2008, it had recently been painted and looked very spruce.

The original design called for standard square tenders but, at the time the DM&IR locomotives were being designed, the UP’s Big Boy 4-10-0 centipede tender was in production. These appealed to DM&IR as they brought an additional 3,000 gallon water capacity.