Only 72 Yellowstones were built (in five different classes). They were owned by the roads listed in the table below.
| Railroad Line | Class | Road Numbers | Quantity |
|---|---|---|---|
| Northern Pacific | Z-5 | 5000-5011 | 12 |
| Southern Pacific | AC-9 | 3800-3811 | 12 |
| Duluth, Missabe & Iron Range | M-3 | 220-227 | 8 |
| Duluth, Missabe & Iron Range | M-4 | 228-237 | 10 |
| Baltimore & Ohio | EM-1 | 7600-7629 | 30 |
Each class of Yellowstone was a different design (except for the two classes owned by the DM&IR). The design was usually dictated by the specific needs of the railroad that received them.
The first Yellowstone was built in 1928 by ALCO for the Northern Pacific for
running throughout the high speed plains of North Dakota. It would turn out
to be the one and only Yellowstone that ALCO would build.
NP wanted to burn low-grade Rosebud coal (obtained from mines along the line) in their locomotives. This required the Yellowstone to be designed with a huge (the largest ever used on a steam locomotive) firebox (182 sq. ft.). The front half of the firebox was over the two rear pairs of drivers, and the trailing truck (which was equipped with a booster).
It was the largest steam locomotive in the world (at that time) and ALCO celebrated by serving dinner to 12 people seated in the firebox! NP asked for bids for 11 more like it, and Baldwin got the job in 1930. The NP Yellowstones steamed poorly and produced less that 5,000 HP. NP found that the grates were simply too large to maintain a high temperature and complete combustion. The combustion problem was solved by blocking off The front two feet of the firebox on each locomotive. At some point the Z-5s were upgraded with roller bearings.
Most of Southern Pacifics "big steam" were of the Cab Forward design (a backwards Yellowstone).
However, not all of the SP "big steam" was required to run through the snow
sheds of the Sierras. In 1939 the SP received 12 Yellowstones from Lima for
use throughout the southern part of the SP system. Unlike the Cab Forwards,
the class AC-9 locomotives were built as coal burners. They were later
converted to burn oil. Also, the AC-9 class had a grate area of 146 sq. ft.
rather than the 139 sq. ft. of their cab forward siblings. With their
skyline casings and striped cowcatcher-pilots, they could almost be
considered streamlined. They were retired between 1953 and 1956. The photo
was taken near Tucumcari, NM on May 11, 1940 by Richard H. Kindig.
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 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. I had once read that it was the task of returning ore cars up this hill where these Yellowstones worked their hardest. However, someone else has informed me that the Yellowstones were never used to pull empties from Duluth to Proctor (older 2-8-8-2s, newer 2-10-4s and 0-10-2s were used for this service). Yet another person said that he spoke to a couple people (including the diesel shop forman 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 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 or the more difficult tasks for the Yellowstones. They were all retired between 1958 and 1963.
Yellowstone 221 was displayed for many years near the ore docks in the city
of Two Harbors, MN. By the late 1960s, the locomotive was showing signs of
severe decay. In 1967, the DM&IR felt it had deteriorated to such a point
that warranted its removal and 221 was pulled to the Proctor roundhouse by an
SD9 and later sold for scrap. See TRAINS, November 1967 for
details.
On February 7, 1943, a Denver & Salt Lake wrecker comes
to grips with front end of Missabe Road 224 at Fireclay, CO after runaway
while in Rio Grande employ. Looks pretty rough, doesn't it.
M-3 225 leads a railfan excursion across a DM&IR trestle near Holman
Junction in the late 1950s. Today 225 is on display in Proctor, MN.
Proctor is a few miles west of Duluth and the site of a large railroad yard.
In 1995 225 had all of the boiler jacketing removed giving it this "white"
appearance. This will probably extend its life on display as moisture will
not be trapped against the boiler. Since the time this photo was taken, 225
has been painted and is looking pretty nice.
Yellowstone 227 was stored at the Proctor roundhouse until 1967. It is now
on display inside the Lake Superior Transportation Museum. As a result, it
is difficult to get a decent photograph of her. This postcard was taken
years ago when she was still outside. Today, her driving wheels are
supported slightly above the railheads. An electric motor is used to spin
her wheels slowly so that you can see the motion of the massive valve gear.
Of the three surviving Yellowstones, 227 is probably in the best shape.
On June 2, 1967, Yellowstone 229 was pulled from the Proctor roundhouse where
it had been stored and placed on display in Two Harbors replacing Yellowstone
221 which had deteriorated from exposure to the weather. A small shed was
built over 229 to help protect her from the weather.
Here 232 is shown waiting to be scrapped. A row of centipede tenders
detached from their locomotives, yet still full of coal, is on the right.
Notice that the first tender belongs to 227 (which is now on display in
Duluth). The DM&IR switched the tenders for their steamers around near the
end of their careers to keep the best of the equipment in operation. The
227's tender was sent to the Paper Calmenson scrap yard 11-9-62 with steamer
231. 229 has 222's tender, and 227 has 231's tender.
Number 234 is viewed with a train of 180 cars at Payne, MN on September 30,
1957. Photo courtesy: Walter R. Evans.
The EM-1s were the last articulated steam locomotives built for the B&O.
Actually, the B&O did not want the EM-1s. Instead they wanted diesels.
However, because of restrictions imposed by the War Production Board, the
EM-1s were delivered from Baldwin in 1944 (7620 - 7619) and 1945 (7620 -
7629). For this wheel arrangement, they were relatively modest in size,
but very successful. Originally, they worked on the Cumberland Division,
a very physically difficult stretch of the B&O, with numerous heavy coal
trains, as well as fast freights. The main district served by the EM-1
was the line from Cumberland towards Grafton, WV. Later, as diesels took
over this assignment, the class was shifted to the Pittsburgh Division,
where they primarily handled Lake Mineral traffic, plus trains between
Wheeling and Pittsburgh. The class was renumbered 650-679. They started
to be scrapped in 1957, and all were off the roster by 1960.
| Type | NP Z-5 | SP AC-9 | DM&IR M-3 | DM&IR M-4 | B&O EM-1 | UP 4884-1 | WP M-137/151 |
|---|---|---|---|---|---|---|---|
| Series | 5000 | 3800-3811 | 220-237 | 228-237 | 7600-7619 | 4000-4019 | (10) |
| Cyl:dia x stroke | 26x32 | 24x32 | 26x32 | 26x32 | 24x32 | 23.75x32 | 26x32 |
| Driver diameter | 63 | 63.5 | 63 | 63 | 64 | 68 | 63 |
| Boiler pressure | 250 | 250 | 240 | 240 | 235 | 300 | 250 |
| Grate area | 182 | 139.3 | 125 | 125 | 117.5 | 150 | |
| Evaporative heating surface | 7673 | 6918 | 6780 | 6758/6780 | 5298 | 5889 | |
| Superheater heating surface | 3219 | 2831 | 2770 | 2770 | 2118 | 2466 | |
| Weight on drivers | 554,000 | 531,200 | 560,257 | 564,974 | 485,000 | 540,000 | 552,700 |
| Total engine weight | 715,000 | 689,900 | 695,040 | 699,700 | 628,700 | 762,000 | |
| Tender weight | 401,000 | 400,700 | 436,635 | 438,335 | 382,000 | 427,500 | |
| Tractive force engine | 145,930 | 124,300 | 140,000 | 140,000 | 115,000 | 135,375 | 137,000 |
| Tractive force booster | 13,400 | None | None | None | None | None | 13,900 |
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