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.
|Class||Qty.||Road Numbers||Later Numbers||Year Built||Builder||Notes|
|L1||20||8500-8519||750-769||1909||CMSt.P&P||scrapped between 1945 and 1954|
|L2||40||8000-8039||600-682||1912-1913||CMSt.P&P||scrapped between 1930 and 1955|
|L2||115||8040-8154||612-726||1912||ALCO||scrapped between 1934 and 1954|
|L2||25||8155-8179||661-738||1914||ALCO||scrapped between 1935 and 1954|
|L3||100||8600-8699||300-399||1918-1919||ALCO||USRA allocated "Mikado-Heavy" locomotives. All scrapped between 1938 and 1956.|
|L2||100||8200-8299||500-598||1920-1921||Baldwin||scrapped between 1935 and 1954|
|L2||100||8300-8399||400-499||1922-1923||Baldwin||scrapped between 1950 and 1956|
Data from MILWRD 1930ca locomotive diagram book supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. See also Jim Scribbins, "Chicago, Milwaukee, St Paul & Pacific (Milwaukee Road) in George H Drury, Guide to North American Steam Locomotives (rev ed.) (Waukesha, WI: Kalmbach Books, 2015), p.134.These were, according to Jim Scribbins, "basically enlarged Prairies [2-6-2].". 65 sq ft (6.04 sq m) of direct heating surface came from the combustion chamber. On the one hand, being delivered with a saturated boiler puts them in the first period of Mikado development, but rolling on 63" drivers and adding a combustion chamber point toward futher 2- 8- 2 developments. The shops later fitted some of the class with superheaters. Only four L1s went to the scrapper before the US entered World War II. Ten of the remaning 16 remained in service in to the 1950s.
Data from Milwrd 1930ca Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange.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.
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.
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.
Data from MILWRD 1945 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange collection. See also Jim Scribbins, "Chicago, Milwaukee, St Paul & Pacific (Milwaukee Road)" in George H Drury, Guide to North American Steam Locomotives, Revised Edition (Waukesha, WI: Kalmbach Books, 2015), p. 134.(Thanks to John Werth for his 24 July 2021 email noting the Wilson feed water heater.) for the Wilson system: "Milwaukee's S2's: Any Milwaukee Steam Experts Out Ther[e?]" thread begun by rcall30160 [Bob Callahan] on 4 June 2010 and Larry Doyle's response on 5 June 2010 on the trainorders forum at ,2203733 and Larry Doyle, "Wilson Feedwater Heater", posted 14 June 2019 at ,4810774, last accessed 24 July 2021. Alco's Brooks and Schenectady Works divided evenly the production of these USRA Heavy Mikados (Locobase 41). Brooks's works numbers were 59740-59776 in September 1918, 59777-59789 in October. Schenectady delivered its 50 as works numbers 61042-61046, 61148-61167 in March 1919, 61168 in May, 61175 in June; 61170-61172 , 61174, 61176, 61179 in July; and 61169, 61173, 61177-61178, and 61183-61192 in August. The 100 Heavy Mikados, most assigned to a single railroad, proved well-suited to the Milwaukee's motive power needs. Jim Scribbins, writing in Drury 1993, 2015, commented that they were "the most powerful road engines until the 4-8-4s arrived." He add that they proved "particularly successful on the main line between Minneapolis and Harlowton [Mont.], on the routes to the Indiana coal fields, and in iron-ore service in upper Michigan." Firebox heating surface area included 29 sq ft (2.69 sq m) in arch tubes. Fourteen locomotives fitted with Franklin trailing-truck boosters fell into subclass L-3a: 8605, 8608, 8610-8611, 8614, 8616, 8620-8621, 8631, 8639, 8645, 8650, 8653, 8656-8657, 8660, 8674, 8679, 8691. (300-314 and 354, 359-360, 363 in the 1938 renumbering). Nine of these had been fitted with Wilson feed water heaters by the 1930s: 8608, 8614, 8616, 8620, 8639, 8645, 8691. Two more boosterless locomotives--8671, 8685--also had feed water heaters. Wilson's 1929 patent filing (US1901216) describes the original design. Larry Doyle's 2010 response in trainorders (cited above) reported the installation lay in "in a hot well in the tender, with a large [6" (152 mm) diameter] exhaust steam pipe running on the left side of the engine from the cylinders to the tender". Baldwin Magazine's report described the Wilson Locomotive Water Conditioner in similar terms. Doyle returned to the Wilson feed water heater in the trainorders forum in 2019 with a full quote of an article by former Milwaukee Road engineer Bill Wilkerson (It too is cited above in the second trainorders entry.). Wilkerson's detailed discussion of the weaknesses in the design as it interacted with operating conditions is too long to quote again in full in this entry. But a summary of his comments should include the following: A thermostat valve needed to work properly all the time and scale laid on the valve by hard water in Montana and the Dakotas usually resulted in heating all of the tender's water to boiling. Hand valves that could control the steam "were all located in the most inaccessible place on the engine." To operate that valve on L3s, the fireman had to crawl out on the running board on the left side, "then lay down and reach down to get the valve." That wasn't the end of the mischief. Boiling water coming forward to be let into the boiler used an impeller pump. If the pump became "steam-bound", it would let the steam turbine "over-speed and lock-out." Trainorders comments speculated on whether firemen just pretended the system was broken and bypassed it somehow. Doyle added later: "I would suspect, from Wilkersons description, that these things were probably very noisy in operation, as well. "I'd think it would be about like closing the overflow valve on a lifting injector and fully turning on the steam to it. To those who haven't experienced that, it's sorta like boiling a large potato kettle on a kitchen stove, but several hundred times louder. The whole tender shakes." ( Locobase found a later patent (US1884051A) described a boiler-mounted "pre-heater". It consisted of a bundle of tubes within a closed unit. As feed water entered the tube bundle, it was heated by exhaust steam. Locobase can't be sure if this was meant to be an added component or a replacement for the tender system. Nor can he say if any of these preheaters were produced.) The L3s' backbones were one-piece cast steel beds from General Steel Castings Corporation. Boxpok drivers turned on Timken roller bearings, as did the front truck's wheels; rear truck and tender wheels used American Steel Foundries roller bearings. By 1945, boilers on all of the engines were pressed to 200 psi (13,8 bar) which increased tractive effort to 62,949 lb (280.0 kN; 28,553 kg) . Fitting thicker tires increased nominal driver diameter on some locomotives to 64", slightly reducing tractive effort to 61,965 lb (275,63 kN; .28,107 kg). Except for 336 (ex-8629), the entire stud served untl the late 1940s into the mid-1950s.
Principal Dimensions by Steve Llanso of Sweat House Media
|Class||L1||L2||L2-a||L2-b||L3, L3-a, b (USRA)|
|Railroad||Milwaukee Road (CMStP&P)||Milwaukee Road (CMStP&P)||Milwaukee Road (CMStP&P)||Milwaukee Road (CMStP&P)||Milwaukee Road (CMStP&P)|
|Number in Class||20||180||100||100||100|
|Road Numbers||2500-2519/8500-8519/750-767||8000-8179||8200-8299 / 500-598||8300-8399||8600-8699/300-399|
|Builder||Milwaukee||several||Baldwin||Baldwin||Alco - multiple works|
|Locomotive Length and Weight|
|Driver Wheelbase (ft / m)||16.50 / 5.03||16.50 / 5.03||16.50 / 5.03||16.50 / 5.03||16.75 / 5.11|
|Engine Wheelbase (ft / m)||35.08 / 10.69||35.08 / 10.69||35.25 / 10.74||35.25 / 10.74||36.10 / 11|
|Ratio of driving wheelbase to overall engine wheelbase||0.47||0.47||0.47||0.47||0.46|
|Overall Wheelbase (engine & tender) (ft / m)||65.60 / 19.99||66.69 / 20.33||66.69 / 20.33||70.54 / 21.50||72.17 / 22|
|Axle Loading (Maximum Weight per Axle) (lbs / kg)||56,300 / 25,537|
|Weight on Drivers (lbs / kg)||201,000 / 91,172||216,500 / 98,203||219,000 / 99,337||219,000 / 99,337||243,000 / 110,223|
|Engine Weight (lbs / kg)||260,500 / 118,161||275,000 / 124,738||289,000 / 131,088||289,000 / 131,088||320,000 / 145,150|
|Tender Loaded Weight (lbs / kg)||154,000 / 69,853||156,000 / 70,760||155,000 / 70,307||180,000 / 81,647||183,800 / 83,370|
|Total Engine and Tender Weight (lbs / kg)||414,500 / 188,014||431,000 / 195,498||444,000 / 201,395||469,000 / 212,735||503,800 / 228,520|
|Tender Water Capacity (gals / ML)||8000 / 30.30||8500 / 32.20||8500 / 32.20||10,000 / 37.88||10,000 / 37.88|
|Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT)||14 / 13||11 / 10||12 / 11||16 / 15||16 / 15|
|Minimum weight of rail (calculated) (lb/yd / kg/m)||84 / 42||90 / 45||91 / 45.50||91 / 45.50||101 / 50.50|
|Geometry Relating to Tractive Effort|
|Driver Diameter (in / mm)||63 / 1600||63 / 1600||63 / 1600||63 / 1600||63 / 1600|
|Boiler Pressure (psi / kPa)||200 / 13.80||200 / 13.80||200 / 13.80||200 / 13.80||190 / 13.10|
|High Pressure Cylinders (dia x stroke) (in / mm)||24" x 30" / 610x762||26" x 30" / 660x762||26" x 30" / 660x762||26" x 30" / 660x762||27" x 32" / 686x813|
|Tractive Effort (lbs / kg)||46,629 / 21150.58||54,724 / 24822.42||54,724 / 24822.42||54,724 / 24822.42||59,801 / 27125.31|
|Factor of Adhesion (Weight on Drivers/Tractive Effort)||4.31||3.96||4.00||4.00||4.06|
|Tubes (number - dia) (in / mm)||366 - 2" / 51||226 - 2" / 51||226 - 2" / 51||198 - 2" / 51||243 - 2.25" / 57|
|Flues (number - dia) (in / mm)||30 - 5.375" / 137||30 - 5.375" / 137||34 - 5.375" / 137||45 - 5.5" / 140|
|Flue/Tube length (ft / m)||17.52 / 5.34||17.51 / 5.18||17.50 / 5.33||17.50 / 5.33||19 / 5.79|
|Firebox Area (sq ft / m2)||282 / 26.21||258 / 23.98||310 / 28.80||311 / 28.89||316 / 29.36|
|Grate Area (sq ft / m2)||48.80 / 4.54||48.80 / 4.54||49.12 / 4.56||48.80 / 4.53||70.50 / 6.55|
|Evaporative Heating Surface (sq ft / m2)||3614 / 335.87||3050 / 283.46||3106 / 288.55||2950 / 274.06||4314 / 400.78|
|Superheating Surface (sq ft / m2)||640 / 59.48||645 / 59.92||720 / 66.89||993 / 92.25|
|Combined Heating Surface (sq ft / m2)||3614 / 335.87||3690 / 342.94||3751 / 348.47||3670 / 340.95||5307 / 493.03|
|Evaporative Heating Surface/Cylinder Volume||230.04||165.40||168.44||159.98||203.39|
|Computations Relating to Power Output (More Information)|
|Robert LeMassena's Power Computation||9760||9760||9824||9760||13,395|
|Same as above plus superheater percentage||9760||11,419||11,494||11,712||15,940|
|Same as above but substitute firebox area for grate area||56,400||60,372||72,540||74,640||71,448|