Three Cylinder Steam Locomotives
As far as I know, there are only five surviving 3-cylinder rod steam
locomotives in the United States (this, of course, does not include all
of the 3-cylinder Shay type locomotives). They include:
- Southern Pacific 4-10-2 5021 at the Los Angeles Co. Fairplex, Pomona, CA (Southern California Chapter Railway and Locomotive Historical Society)
- Union Pacific 4-12-2 9000 at the Los Angeles Co. Fairplex, Pomona, CA (Southern California Chapter Railway and Locomotive Historical Society)
- Alton & Southern 0-8-0 12 at the Museum of Transportation, St. Louis, MO
- London & North Eastern Railway 4-6-2 60008 at the National Railroad Museum, Green Bay, WI
- Baldwin 4-10-2 60000 at the Franklin Institute Science Museum, Philadelphia, PA
Southern Pacific 4-10-2 Number 5021
This is the only surviving Southern Pacific three-cylinder 4-10-2 (out of 49).
The first of this type was built in 1925 by ALCO. The first axle is cranked to
allow clearance for the center connecting rod on the second axle. The Southern
Pacific named this wheel arrangement after their own name (Southern Pacific).
The Union Pacific also had locomotives (10) of this wheel arrangement (none
survived). They named them "Overlands". This locomotive has 63 inch drivers.
With its three cylinders, it could develop 4,100 HP. Its top speed was 60 MPH.
They were used for both freight and passenger service over Donner Pass until it
was determined that they were too rigid for the curves on that line. 5021 is in
maintained in excellent condition.
Union Pacific 4-12-2 Number 9000
The 9000 recently had the majority of the asbestos removed (everywhere
except in the cab). The boiler jacket is off and set aside for re-use or
fabrication of new pieces, as needed.
The UP 9000s had two outside 27"x32" cylinders driving the third set of drive
wheels and a third 27"x31" cylinder in the center driving the second axle.
The 9000s had 67 inch drivers. They were constructed with "blind" driver
tires on the third and fourth axles, that is, without the usual flanges,
in an effort to promote easy passage through tight curves. The blind
drivers were found to be unnecessary as tests of the first 4-12-2 proved
the usefulness of the lateral motion devices fitted to the first and sixth
driving axles. There was an attempt to see if they could negotiate the
Oregon Short Line in the Mountains of Oregon. The test failed and they
were returned to the prairies of Nebraska for which they were designed in
the first place.
There is an extremely accurately detailed model of
the UP 4-12-2 available for general viewing at the Schenectady Museum, in
Schenectady, NY. The model is in a section of the museum called the
Schenectady Heritage Area. The model provides an excellent view of the
lateral motion devices fitted to the first and last driving axles, spring
rigging, main and side rod designs, cylinder configurations, valve gear
arrangements, etc. The model is covered by a clear plexiglass cover which
allows for viewing but no touching.
1st Axle Clearance Crank?
There has been some disagreement on whether or not the first drive axle
on this class of locomotives has a 'clearance crank'. The typical
configuration for a three-cylinder steam locomotives is to have a
cranked first axle so that clearance is provided to the connecting rod
that is connected to the second set of drive wheels. The Guide to
North American Steam Locomotives by George Drury states that the
first axle is cranked. I have also received e-mail which stated that
the first axle has a crank. However, I have been in contact with John E. Bush who was the co-author
of an excellent reference book on these locomotives (Volume 2 of The
Union Pacific Type by Kratville and Bush). This book has several
photos which show quite clearly that it does not have a 'clearance crank'
on the first axle. Instead, it explains, the builders added 18 inches to
the distance between the first two axle centers, thus precluding the need
for a 'clearance crank' on the first driving axle. This has been verified
by Barry Koeb who is the R&LHS member responsible for the UP 9000 who
has been inside the frame of the 9000. I am now convinced that the first
axle on this class of locomotives did not have a crank. The last time
I was in LA, I tried to look under 9000 and photograph the first axle.
However, the front of this locomotive is so tightly packed that I could
not see the front axle let alone photograph it.
In summary, the 9000's designers wanted to avoid having to put a crank in
the axle of driver number 1. So they did the following things:
- They increased the distance between the #1 and #2 drivers by about 18" over the spacing between the other drivers.
- They increased the distance between driver #1 and the cylinder saddle.
- They raised the middle cylinder to about 9" above a line parallel to the two outside cylinders.
Driver "Quartering" and Valve Gear
I have been told that the designers had to keep the quartering at equal 120
degree angles partially for centrifugal mass balancing reasons. However,
if the inside cylinder is inclined at say 7°, it would normally be
necessary to set the cranks at 120°-127°-113° to preserve the
torque distribution. Apparently, this was not necessary for the 9000s.
The #2 driver has an enormous inside steel crank/counterbalance assembly
that has to spin in concert with, and balanced to, the outside main rods.
(One hundred and twenty degrees is the quartering angle listed in the book
"Union Pacific Type, Volume 1" and confirmed by one of the co-authors,
John Bush.) It is suspected that one of the reasons the Baldwin #60000
used a 90°-135°-135° configuration had to do with it being
a compound locomotive, with the center cylinder receiving high-pressure
boiler steam, and the outer cylinders receiving the low-pressure steam
from the center cylinder. And according to John Bush, the locomotive had
"a very interesting" outside valve gear design. The original valve gear
used a conjugated assembly that synthesized inner cylinder valve gear
motion from the outer valve gear on either side of the locomotive.
Many have pointed out the "lopping" exhaust rhythm one hears in recordings
of the 9000 class. The sound may be the result of a number of factors:
When released from shops with running gear trammed "to dimension" and valves
set correctly, a 9000 had a very even 1-2-3, 1-2-3 beat. All of the main
dimensions were the same for the outside and inside cylinders (except that
the inside cylinder was one inch shorter) and valves and when everything
was right they were square like any engine, only with six exhausts per
revolution. Like other power, the unevenness developed as miles grew,
and in particular as maintenance forces allowed the inside main rod to
languish! If you've heard Howard Fogg's recordings of 9009 on his great
album "The Big Steam" and think thats what a 4-12-2 regularly sounded like
please consider it as virtually totally unrepresentative of their sound.
That engine was horribly out of time and in fact would scare one at speed.
When badly out of dimension, engines can begin working against themselves.
- The center cylinder being located just below the exhaust jet means that its exhausted steam had a shorter distance to travel before hitting the stack, as opposed to the longer path the outer cylinder's exhaust had to move. So, it was likely that its exhaust 'beat' hit sooner, and louder.
- The center cylinder stroke is one inch less than the outside cylinders, which could have resulted in slightly earlier exhaust sounds.
- A lack of maintenance on the center cylinder might have lead to uneven bearing wear resulting in an uneven exhaust sound.
Other Long, Rigid Wheelbase Steam Locomotives
The UP 9000s had the longest rigid wheelbase of all steam locomotives in the
United States. However, there were a few other countries with equally
impressive locomotives. Bulgaria and two groups of 2-12-4Ts, Indonesia had a
few 2-12-2Ts. Russia built one 4-14-4 (classified as a 2-7-2). It made one
demonstration run during which it tore the track apart -- it was stored and
later scrapped. It was designed shortly after a group of thirty young Soviet
engineers toured the USA in 1930 and 1931. They saw the last of the Union
Pacific 4-12-2s being built by Alco's Dunkirk New York shop. Steam locomotive
historians consider the Soviet 4-14-4 to be an example of the Russian's trying
to outdo the Americanskiies. The Russians learned many useful things during
their tour, and did develop a successful 2-10-2 freight engine and a 2-8-4
passenger locomotive using ideas they picked up from Alco and Baldwin.
Other UP 9000 Web Pages
Alton & Southern 0-8-0 12
This Alton & Southern 0-8-0 is located at the Museum of Transportation in
St. Louis, MO. It was built by ALCO in 1926 and cost $57,598.20. It
ran up 622,626 miles in service and was donated to the museum in 1948. Here
is the locomotive data from its builders photo:
|American Locomotive Company|
|Class 080 S 243, "Three-Cylinder"||Road Number 12|
|Built for the Alton & Southern|
|Gauge of Track||Cylinders||Driving Wheel Diameter||Boiler||Fire Box||Tubes|
|4'-8 1/2"||22"||28"||57"||76"||200 lbs||96"||84 1/4"||239|
|Wheel Base||Weight in Working Order - Pounds|
|Driving||Engine||Engine & Tender||Driving||Engine||Tender|
|Fuel||Evaporating Surfaces, Square Ft.||Superheating Surface Square Ft.||Grate Area Sq. Ft.||Maximum Tractive Power||Factor of Adhesion|
|Kind||Tubes||Flues||Fire Box||Arch Tubes||Total|
|Soft Coal||1991||871||186||23||3071||740||56.1||60600 lbs||4.0|
Order No S-1560
|Tender Type 8-Wheeled.||Capacity Water 9000 gals||Fuel 14 tons|
London & North Eastern Railway 4-6-2 60008
This three cylinder Pacific, named Dwight D. Eisenhower,
is displayed at the National Railroad Museum in Green Bay, Wisconsin.
It was originally named Golden Shuttle but was renamed in late
1945. It was built by the LNER as the A4 class, introduced in Sept 1935.
There were 35 in the class. When British Railways was formed in 1946
by the amalgamation of four "Groups", there was some number duplication
on locomotives. Block numbers were allocated the four former groups
of locomotives. Former LNER locos were numbered in the series starting
at 60000. That is how 60008 (formerly number 8) came about.
Data taken from "British Locomotive Classes" Promotional Reprint Company
1996. First published by the Locomotive Publishing Company 1945 entitled
Modern Locomotive Classes. The locos modified during the war, with sections
of the streamline casing removed, so the weights may be wrong for your
engine. Further, some engines had double chimneys with Kylchap exhaust
systems. The record breaking engine Mallard (126 mph) was so equipped.
|Boiler max. O.D.:||6' - 5"|
|Grate area:||41.2 sq. ft.|
|Heating surface firebox + combustion chamber:||231 sq ft|
|Total evaporative surface:||2576 sq ft|
|Length between tube plates:||17' - 11.75"|
|Superheater surface:||750 sq ft|
|Operating pressure:||250 psi|
|Cylinders:||(3) 18.5" dia by 26" stroke|
|Valve Gear:||Walschaerts with Gresley derived motion for inside cylinder|
|Steam lap/Max travel:||1 5/8" / 5 3/4"|
|Locomotive Weight:||102 ton 19 cwt|
|Tender Weight:||64 ton 3 cwt|
|Tender capacity:||8 tons coal, 5000 gallons water|
|Axle weight:||22 tons|
Baldwin Demonstrator Number 60000
With the year 1926 came an outstanding event in Baldwin's history, for at
that time the Works was ready to build its sixty-thousandth locomotive. To
symbolize this event President Samuel M. Vauclain planned and built a huge
three-cylinder compound, high-pressure locomotive. It was of the 4-10-2
type and closely resembled engines with this wheel arrangement on the
Southern Pacific Railroad. To safely accommodate the high boiler pressure
of 350 lb. per square inch, a water-tube firebox was used.
Built as a Baldwin demonstrator in 1926, this locomotive was used by
various railroads around the country to show some of Baldwin's latest
ideas. It was numbered 60000 to commemorate the 60,000th locomotive to be
built by the Baldwin Locomotive Works. It ran successfully on either coal
or oil as fuel. It also attained the highest power ever developed up to
the time on the Altoona test plant, namely, 4,500 horsepower. This, at the
time, exceeded the plant's capacity and restricted attempts to obtain
greater power with additional tests. It has several features which made it
From the book The Locomotives that Baldwin Built by Fred Westing
NOTE: If you look carefully under the smokebox front, you will see the
center high-pressure cylinder and steam chest. This cylinder is angled
downward to the back. The piston is connected via a crank to the second
set of drivers.
- It has a water tube firebox.
- It has three cylinders.
- It used compound steam expansion.
The numbers 60000 appear on the cab side, and on the number boards and
headlight of the engine. The tender lettering reads THE BALDWIN LOCOMOTIVE
WORKS. The tender is a Vanderbilt with a short coal space and 6-wheel
trucks. Here are a few more specifications on the 60000:
Although there were not any serious problems with it, the railroads rejected
it because they found it overly heavy and complex and were wary of most of
its features. Also, the 4-8-4 was quickly becoming the ideal high-speed,
heavy freight and passenger locomotive. With only 100,000 miles on it
(very little for a steam locomotive), it was returned to Philadelphia in
1928 and stored until 1932 when it was donated to the Franklin Institute
Science Museum in Philadelphia, PA.
- Wheel arrangement: 4-10-2
- Cylinders: High pressure (1) 27x32 inches
- Cylinders: Low pressure (2) 27x32 inches
- Boiler diameter: 84 inches
- Steam pressure: 350 psi
- Driver diameter: 63.5 inches
- Weight on drivers: 338,400 lbs
- Total engine weight: 457,500 lbs
- Total engine & tender weight: 700,900 lbs
- Tractive force: 82,500 lbs
It is on display there today in the basement on a short piece of track. A
hydraulic system is used to move the locomotive back and forth about fifteen
feet. The demo was once propelled by a worm gear. It was changed over to a
hydraulic system in the mid 1970s. By that time, the bearings in the drivers
had become egg shaped, supposedly because of all the reversing, and some BLH
retirees figured out how to replace them. The distance traveled inside the
museum was staggering for such a short trip: conservatively, 30 ft/trip x 2
trips/demo x 5 demos/day x 360 operating days/yr = about 20 miles/yr, or
about 400 miles in reverse by 1980.
Other Pages on the Baldwin 60,000
Other 3-Cylinder Steam
Baldwin built a batch of 3-cylinder pacifics for the EFCB (Central of
Brazil) in 1927. They were broad gauge machines (5ft 3") (Brazil Central
had both 5'-3" and Metre gauge lines). One of these is preserved in working
order and operates about once a month. It is stored at the Museum of the
Immigrants in Sao Paulo.
3-Cylinder Steam Reference
- 4-10-2: Three Barrels of Steam by Boynton.
- Vintage Rails magazine, No 15, November/December 1998, Pentrex
- Union Pacific Type Volume 2, by Kratville and Bush