Like the Erie's Triplex 2-8-8-8-2s, this single locomotive showed all the limitations of trying to cram so much tractive power under one boiler.
Although this design had slightly smaller cylinders under a slightly larger boiler, the grate and evaporative heating surface were still too small. The small firebox gained some additional direct heating surface from the 72 sq ft (6.7 sq m) of arch tubes supporting the brick arch. A Baldwin feed water heater contained 437 sq ft (40.6 sq m). All six cylinders admitted steam through 14-inch (356 mm) piston valves.
The specifications included the requirement that the engine drag 2,580 tons (2,345 metric tonnes) of cars and leading from Elmore to Clark's Gap over 14 miles (22.5 km) of track of which 12 miles (19.3 km) ascended at 2.07% and wound around ten 12-degree curves. Four-fifths of the load (2,064 tons or 1,876 metric tonnes) were to go up the grade at 10 mph (16 km/h).
Drury (1993) notes that compared to the Erie engines, the 700 "was slower and ran out of steam faster[!]..." He adds that one tunnel had only four inches of clearance, which must have made a passage hell on earth for the locomotive and its crew. "It never made a successful trip," according to Drury.
The engine units were turned into a 2-8-8-0 Mallet and a 2-8-2 Mikado (Locobase 7486), each of which ran until 1953.
|Specifications by Steve Llanso|
|Locomotive Length and Weight|
|Ratio of driving wheelbase to overall engine wheebase||0.23|
|Overall Wheelbase (engine & tender)||91.25'|
|Axle Loading (Maximum Weight per Axle)||62000 lbs|
|Weight on Drivers||725475 lbs|
|Engine Weight||842310 lbs|
|Tender Light Weight|
|Total Engine and Tender Weight||842310 lbs|
|Tender Water Capacity||13000 gals|
|Tender Fuel Capacity (oil/coal)||24000 gals|
|Minimum weight of rail (calculated) on which locomotive could run||101 lb/yard|
|Geometry Relating to Tractive Effort|
|Boiler Pressure||222 psi|
|High Pressure Cylinders (dia x stroke)||34" x 32" (2)|
|Low Pressure Cylinders (dia x stroke)||34" x 32" (4)|
|Tractive Effort||186975 lbs|
|Factor of Adhesion (Weight on Drivers/Tractive Effort)||3.88|
|Firebox Area||431 sq. ft|
|Grate Area||107.60 sq. ft|
|Evaporative Heating Surface||8120 sq. ft|
|Superheating Surface||2059 sq. ft|
|Combined Heating Surface||10179 sq. ft|
|Evaporative Heating Surface/Cylinder Volume||241.47|
|Computations Relating to Power Output (More Information)|
|Robert LeMassena's Power Computation||23887|
|Same as above plus superheater percentage||28665|
|Same as above but substitute firebox area for grate area||114818|