Western Maryland 2-8-8-2 "Chesapeake" Locomotives in the USA

Class Details by Steve Llanso of Sweat House Media

Class L1 (Locobase 331)

Data from a table in January 1917 issue of Railway Mechanical Engineer, supplemented by data from WM MISC steam locomotive diagram book supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. Works numbers were 5085-5094 in December 1915 and 5095-5099 in January 1916.

L-series Mallet compounds came in 3 batches, all of which had the same simple (as listed) and compound TE (105,600 lb).

L1s (901-910) put 451,800 lb on the drivers and had a total engine weight of 506,500 lb.

L1-a (911-915) drivers supported 455,600 lb and total weight was 503,100 lb.

The L2 class numbered 916-925 and are shown in Locobase 8888.

Locobase is struck by the timing of this contract. Lima had entered the market for full-size mainline power in 1911; for the builder to be offering such a large engine--its first sale of a Mallet--indicates the determination to compete that underlay the decision. Its October 1916 ad for the L class in Railway Mechanical Engineer staked Lima's claim to ride on the leading edge:

"Today's Locomotives Must Be Different

"To carry peak load of modern railroad operation puts locomotive designers to the test.

"Rules and ratios of ten years ago [i.e., 1906] are now obsolete.

"Capacity increasing factors and economy devices have opened a new era and created new possibilities.

"Lima appreciates its responsibility to apply these factors to peak and normal loads.

"This locomotive is a case in point."

The design was in fact competitive with the other US 2-8-8-2 classes then in service, although its cylinder volume was among the smallest. Its mixed valve outfit had 14" (356 mm) piston valves serving the HP cylinders and double-ported slide valves feeding the LPs. Lima's ground-breaking superpower would appear 10 years later.

Drury's (1993) wry comment on the effect on top speed of 52" drivers and 40" LP cylinders suggests the limits of at least this early approach to superpower: "...the freight timetables must have listed days instead of hours and minutes."

Class L1/L2 with larger grate (Locobase 8888)

Data from WM - 1 - 1936 steam locomotive diagram book supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. Works numbers from the range of 5554-5555 in December 1917, 5556-5558 in January 1918, 5559-5563 in April.

Lima's third batch of big Mallets weighed a bit more than the L1s (for which, see Locobase 331), but were otherwise almost identical. Some of the class had Baker valve gear, some were fitted with Walschaert valve gear; all of this class had converted to Walschaert valve gear by 1 February 1938, according to a letter in Volume 41 of the DeGolyer specification bookRail Data Exchange at SMU.

At some later date, several of the L1s and L2s had their grates stretched from 120" (3.048 m) to 150" (3.81 m), which increased the grate area to 100 sq ft (9.3 sq m) and the firebox to 530 sq ft (49.2 sq m). Locobase suspects this was a result of eliminating a combustion chamber ahead of the firebox, especially as the arch tubes had been deleted.

Principal Dimensions by Steve Llanso of Sweat House Media
ClassL1L1/L2 with larger grate
Locobase ID331 8888
RailroadWestern Maryland (WM)Western Maryland (WM)
Number in Class1510
Road Numbers901-915916-925
Number Built15
Valve GearWalschaertBaker
Locomotive Length and Weight
Driver Wheelbase (ft / m)15 / 4.5715 / 4.57
Engine Wheelbase (ft / m)56.67 / 17.2756.67 / 17.27
Ratio of driving wheelbase to overall engine wheebase 0.26 0.26
Overall Wheelbase (engine & tender) (ft / m)91.14 / 27.7891.14 / 27.78
Axle Loading (Maximum Weight per Axle) (lbs / kg)58,700 / 26,62660,300 / 27,352
Weight on Drivers (lbs / kg)451,800 / 204,933469,900 / 213,143
Engine Weight (lbs / kg)506,500 / 229,745504,900 / 229,019
Tender Loaded Weight (lbs / kg)209,500 / 95,028224,600 / 101,877
Total Engine and Tender Weight (lbs / kg)716,000 / 324,773729,500 / 330,896
Tender Water Capacity (gals / ML)10,500 / 39.7712,500 / 47.35
Tender Fuel Capacity (oil/coal) (gals/tons / ML/MT)20 / 18.2020 / 18.20
Minimum weight of rail (calculated) (lb/yd / kg/m)94 / 4798 / 49
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)52 / 132152 / 1321
Boiler Pressure (psi / kPa)210 / 14.50210 / 14.50
High Pressure Cylinders (dia x stroke) (in / mm)26" x 30" / 660x81326" x 30" / 660x762
Low Pressure Cylinders (dia x stroke) (in / mm)40" x 30" / 1016x81340" x 30" / 1016x762
Tractive Effort (lbs / kg)97,877 / 44396.3197,877 / 44396.31
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.62 4.80
Heating Ability
Firebox Area (sq ft / m2)404 / 37.55530 / 49.26
Grate Area (sq ft / m2)80 / 7.43100 / 9.29
Evaporative Heating Surface (sq ft / m2)5693 / 529.095768 / 536.06
Superheating Surface (sq ft / m2)1264 / 117.471380 / 128.25
Combined Heating Surface (sq ft / m2)6957 / 646.567148 / 664.31
Evaporative Heating Surface/Cylinder Volume308.81312.88
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation16,80021,000
Same as above plus superheater percentage19,82424,990
Same as above but substitute firebox area for grate area100,111132,447
Power L179628692
Power MT310.81326.24

All material Copyright © SteamLocomotive.com
Wes Barris