Laramie, Hahn's Peak & Pacific 2-8-2 "Mikado" Locomotives in the USA

Class Details by Steve Llanso of Sweat House Media

Class 4 (Locobase 6580)

Data from 1914 StJ&GI diagram book supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange; and DeGolyer, Volume 39, pp. 29+; and Volume 41, pp. 73+. See also "Union Pacific Subsidiaries -- Coalmont Branch, Wyoming Division -- Laramie, North Park & Western Railroad", on the UtahRails website at []. (This page was last updated on December 29, 2015), last accessed 4 June 2020..(Thanks to James Lowther for commenting on the #8, which uncovered the mystery described below.) Works numbers were 36661 in July 1911, 36786 in August, and 37120-37121 in October.

Firebox heating surface included 23 sq ft (2.14 sq m) of arch tubes. This is an early example of a US Mikado. Its saturated boiler and relatively small dimensions and low boiler pressure mark it as a harbinger of much larger 2-8-2s to come. The engines needed their relatively large grates to burn the lignite coal used as fuel. In six years, the railroad would procure one superheated example of this design; see Locobase 6581.

The LHP&P--aka Late, Hard Pressed and Panicky--went into receivership in 1914 and was taken over by the Colorado, Wyoming & Eastern Railway. The CW&E in turn fell into the hands of a receiver in 1924, when it was reorganized as the Northern Colorado & Eastern Railway. Several months later the NC&E was again reorganized as the Laramie, North Park & Western Railroad (LNP&W).

Locobase found very clear, complete diagrams of all five 2-8-2s in the St Joseph & Grand Island's diagram book nominally dated 9 July 1914. Yet no StJ&GI roster ever showed this set, the #8 described in Locobase 6581, nor any 2-8-2. Moreover, the 8, which was ordered n 1917, appears in the book. Locobase finds a clue to solve this mystery on the estimable UtahRails website.

According to its account, the Union Pacific sought to buy the StJ&GI in 1936. At the same time, the UP wanted to lease the major subsidiaries Los Angeles & Salt Lake, Oregon Short Line and acquire the StJ&GI. Locobase supposes that the UP planned to send alll five Mikados to the StJ&GI after it came under UP control. Locobase supposes it was then that these diagrams were drafted. Objections by both the LNW&P and the Pacific & Idaho Northern led the ICC to require the UP to buy both railroads. The LNW&P came under UP ownership, the P&IN was folded into the OSL

StJ&GI didn't get the quintet. Apparently the UP decided to leave the locomotives on the line they'd served for 20 years and designated thc trackage as the Oakmont Branch. Still operating as the LNW&P Laramie Plains Line, the quartet remained in service through World War Two.

4, 6, and 7 were "vacated" from the roster in June 1947.

Principal Dimensions by Steve Llanso of Sweat House Media

Locobase ID6580
RailroadLaramie, Hahn's Peak & Pacific
Number in Class4
Road Numbers4-7
Number Built4
Valve GearWalschaert
Locomotive Length and Weight
Driver Wheelbase (ft / m)13.08 / 3.99
Engine Wheelbase (ft / m)28 / 8.53
Ratio of driving wheelbase to overall engine wheelbase 0.47
Overall Wheelbase (engine & tender) (ft / m)54.12 / 16.50
Axle Loading (Maximum Weight per Axle) (lbs / kg)
Weight on Drivers (lbs / kg)138,000 / 62,596
Engine Weight (lbs / kg)181,500 / 82,327
Tender Loaded Weight (lbs / kg)114,000 / 51,710
Total Engine and Tender Weight (lbs / kg)295,500 / 134,037
Tender Water Capacity (gals / ML)5500 / 20.83
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT)12 / 11
Minimum weight of rail (calculated) (lb/yd / kg/m)58 / 29
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)48 / 1219
Boiler Pressure (psi / kPa)180 / 12.40
High Pressure Cylinders (dia x stroke) (in / mm)20" x 28" / 508x711
Tractive Effort (lbs / kg)35,700 / 16193.27
Factor of Adhesion (Weight on Drivers/Tractive Effort) 3.87
Heating Ability
Tubes (number - dia) (in / mm)350 - 2" / 51
Flues (number - dia) (in / mm)
Flue/Tube length (ft / m)16.50 / 5.03
Firebox Area (sq ft / m2)201 / 18.67
Grate Area (sq ft / m2)54 / 5.02
Evaporative Heating Surface (sq ft / m2)3208 / 298.03
Superheating Surface (sq ft / m2)
Combined Heating Surface (sq ft / m2)3208 / 298.03
Evaporative Heating Surface/Cylinder Volume315.13
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation9720
Same as above plus superheater percentage9720
Same as above but substitute firebox area for grate area36,180
Power L15959
Power MT380.79

All material Copyright ©
Wes Barris