Milwaukee Road 2-8-2 "Mikado" Type Locomotives

Introduction

The Milwaukee Shops of the Chicago, Milwaukee, St. Paul & Pacific Railroad built the first "Mikado" type locomotives used on the railroad. The shops built twenty of them in 1909. These locomotives were designated as Class L-1 and numbered 8500 through 8519. They had 63" diameter drivers, 24" x 30" cylinders, a 200 psi boiler pressure and they exerted 46,630 pounds of tractive effort and each weighed 260,500 pounds. The firebox was 282 square feet and the evaporative heating surface was 3,614 square feet. The L-1s did not have a superheater.

In 1912 and 1913, the shops built forty more 2-8-2s. This group was designated as Class L-2 and assigned numbers 8000 through 8039. They were similar to the Class L-I "Mikados" except the cylinder diameter was 26 inches, which raised the tractive effort to 54,725 pounds. During 1912 the CMStP&P had the American Locomotive Company build 115 of the Class L-2 locomotives and assigned them road numbers 8040 through 8154 and in 1914, ordered another twenty-five from ALCO, which were delivered the same year and given road numbers 8155 through 8179. The class L-2 locomotives had 63" diameter drivers, 26" x 30" cylinders, a 200 psi boiler pressure and they exerted 54,725 pounds of tractive effort and each weighed 275,000 pounds. The firebox was 258 square feet and the evaporative heating surface was 3,050 square feet and with the superheater the combined heating surface was 3,690 square feet..

In 1918 and 1919, the USRA assigned 100 USRA "Mikado-Heavy" type locomotives to the CMStP&P. This was in fact 43% of this type of locomotive assigned by the USRA. These locomotives were assigned road numbers 8600 through 8699 and were designated as Class L-3. The Class L-3 locomotives had 63" diameter drivers, 27" x 32" cylinders, a 190 psi boiler pressure and they exerted 59,800 pounds of tractive effort and each weighed 325,000 pounds.

The USRA "Mikado-Heavy" Class L-3 locomotives did well on the CMStP&P, but after the War 200 more "Mikados" were ordered from the Baldwin Locomotive Works. These locomotives were very close copies of the Class L-2. Baldwin delivered 100 between 1920 and 1921 and they were assigned road numbers 8200 through 8299 and Baldwin delivered another 100 between 1922 and 1923 and these were given numbers 8300 through 8399. The Class L-2

There are no surviving Milwaukee Road 2-8-2 "Mikado" type locomotives.

Roster by Richard Duley

ClassQty.Road NumbersLater NumbersYear BuiltBuilderNotes
L1208500-8519750-7691909CMSt.P&P1
L2408000-8039600.6821912-1913CMSt.P&P2
L21158040-8154612.7261912ALCO3
L2258155-8179661.7381914ALCO4
L31008600-8699300-3991918-1919ALCO5
L21008200-8299500-5981920-1921Baldwin6
L21008300-8399400-4991922-1923Baldwin7
Notes:
  1. Numbers 8500-8519 scrapped between 1945 and 1954.
  2. Numbers 8000-8039 scrapped between 1930 and 1955.
  3. Numbers 8040-8154 scrapped between 1934 and 1954.
  4. Numbers 8155-8179 scrapped between 1935 and 1954.
  5. Numbers 8600-8699 USRA allocated "Mikado-Heavy" locomotives. All scrapped between 1938 and 1956.
  6. Numbers 8200-8299 scrapped between 1935 and 1954.
  7. Numbers 8300-8399 scrapped between 1950 and 1956.

Class Details by Steve Llanso

Class L1 (Locobase 1192)

Data from MILWRD 1930ca locomotive diagram book supplied in May 2005 by Allen Stanley from his extensive collection.

These were, according to Jim Scribbins (in Drury, 1993), "basically enlarged Prairies [2-6-2]." 65 sq ft of direct heating surface came from the combustion chamber.

Most stayed in service until the 1950s.

Class L2 (Locobase 1191)

Data from Milwrd 1930ca Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive collection.

According to Jim Scribbins writing in Drury (1993), this Mikado design suited the Chicago, Milwaukee, St Paul & Pacific's requirements very well. The Milwaukee shops built 40 in their shops and bought 180 (155 from Brooks in 1912 and 25 from Schenectady in 1914).

After World War I, Baldwin supplied 200 more in 1920-1923 to slightly different designs; see Locobases 15196 and 15197.

Locobase doesn't know why the class began retiring as early as the 1930s, but can tell that some carried on to the end of steam.

Class L2-a (Locobase 15196)

Data from DeGolyer Library, Vol 67, pp. 199. Works numbers were:

1920

August 53596;

September 53624-53625, 53658-53660, 53678-53680, 53708-53711, 53754-53756

October 53819-53821, 53839-53843, 53867, 53913-53917

November 53937-53939, 53970-53973, 54000, 54036-54044, 54093-54097, 54099, 54120, 54125-

54127, 54144-54151

December 54152-54160, 54192-54194, 54197

1921

January 54287-54289, 54315-54320, 54348-54359

February 54542

When the Milwaukee decided to increase its Mikado motive power stock six years after building its own and buying from Alco (Locobase 1191), it went to Eddystone. The design had the same power dimensions and weighed about the same. Piston valves still measured 14" (356 mm) in diameter and the firebox still had 26 sq ft (2.4 sq m) of arch tubes. Also the boiler's distribution of tubes and flues was unchanged.

But the valves were actuated by Baker-Pilliod's radial gear, the grate area grew a bit due a slightly longer grate, the combustion chamber gained four inches (102 mm) and increased its contribution to heating surface area to 65 sq ft (6.05 sq m). It was delivered with a Duplex automatic stoker.

A "Hereafter" note from 24 April 1924 stating that that "No welding whatever will be permitted on forgings" suggests some in-service incidents that ended badly.

Well-suited to the Milwaukee's demands, as were all of the L2s, all but a few L2-as served into the 1950s. The 8280 was withdrawn in July 1935 and 8289 was retired in March 1944. Of the rest, several were retired in late 1949, the bulk in 1950-1953, and the last few in December 1954.

Class L2-b (Locobase 15197)

Data from DeGolyer Library, Vol 67, pp. 211. Works numbers were:

1922

May 55383-55387

July 55541-55542

September 55605-55616, 55663-55668

1923

May 56518-56523, 56577-56586

June 56686-56693

July 56759-56765, 56831-56836

August 56907-56911, 56984-56991

September 57062-57066, 57082-57083, 57171-57181

October 57249-57252, 57265-57365

Locobase had detected a relative insufficiency in superheater heating surface area compared to many other Mikados of the period and apparently so did the Milwaukee some 90 years earlier. The last L2s they procured came from Baldwin (as had the L2a shown in Locobase 15196), but these had boiler changes aimed at remedying that shortcoming.

Like all of the Milwaukee's L2s, this class of -bs satisfied Milwaukee Road requirements for decades and all operated into the 1950s. The first to retire was withdrawn in January 1950, the last nineteen were withdrawn as a group six years later in January 1956.


Specifications by Steve Llanso
ClassL1L2L2-aL2-b
Locobase ID1192 1191 15196 15197
RailroadMilwaukee Road (CMStP&P)Milwaukee Road (CMStP&P)Milwaukee Road (CMStP&P)Milwaukee Road (CMStP&P)
CountryUSAUSAUSAUSA
Whyte2-8-22-8-22-8-22-8-2
Road Numbers8500-85198000-81798200-8299 / 500-5988300-8399
GaugeStdStdStdStd
BuilderMilwaukeeseveralBaldwinBaldwin
Year1909191219201922
Valve GearWalschaertWalschaertBakerWalschaert
Locomotive Length and Weight
Driver Wheelbase16.50'16.50'16.50'16.50'
Engine Wheelbase35.08'35.08'35.25'35.25'
Ratio of driving wheelbase to overall engine wheebase 0.47 0.47 0.47 0.47
Overall Wheelbase (engine & tender)65.60'66.69'66.69'70.54'
Axle Loading (Maximum Weight per Axle)56300 lbs
Weight on Drivers201000 lbs216500 lbs219000 lbs219000 lbs
Engine Weight260500 lbs275000 lbs289000 lbs289000 lbs
Tender Light Weight154000 lbs156000 lbs155000 lbs180000 lbs
Total Engine and Tender Weight414500 lbs431000 lbs444000 lbs469000 lbs
Tender Water Capacity8000 gals8500 gals8500 gals10000 gals
Tender Fuel Capacity (oil/coal)14 tons11 tons12 tons16 tons
Minimum weight of rail (calculated) on which locomotive could run84 lb/yard90 lb/yard91 lb/yard91 lb/yard
Geometry Relating to Tractive Effort
Driver Diameter63"63"63"63"
Boiler Pressure200 psi200 psi200 psi200 psi
Cylinders (dia x stroke)24" x 30"26" x 30"26" x 30"26" x 30"
Tractive Effort46629 lbs54724 lbs54724 lbs54724 lbs
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.31 3.96 4.00 4.00
Heating Ability
Firebox Area282 sq. ft258 sq. ft310 sq. ft311 sq. ft
Grate Area48.80 sq. ft48.80 sq. ft49.12 sq. ft48.80 sq. ft
Evaporative Heating Surface3614 sq. ft3050 sq. ft3106 sq. ft2950 sq. ft
Superheating Surface640 sq. ft645 sq. ft720 sq. ft
Combined Heating Surface3614 sq. ft3690 sq. ft3751 sq. ft3670 sq. ft
Evaporative Heating Surface/Cylinder Volume230.07165.45168.48160.02
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation9760976098249760
Same as above plus superheater percentage9760114191149411712
Same as above but substitute firebox area for grate area56400603727254074640
Power L16717115051191612513
Power MT294.70468.62479.82503.86

Photos

Reference

Credits

Introduction and roster provided by Richard Duley. Class details and specifications provided by Steve Llanso of Sweat House Media.