MTH RailKing FM H10-44 Diesel Engine – Rio Grande


Authorized Retailer Berwyn’s Toys & Trains in Berwyn, Illinois.

  • Road Name: Denver & Rio Grande Western
  • Cab Number: 121 & 123
  • Product Line: RailKing
  • Scale: O Scale
  • High Rail Wheels
  • Proto-Sound 3.0
  • In Stock: Delivered March 2023


SKU: N/A Category:


  MTH Custom Run / MTH Special Run

Fairbanks Morse got into the locomotive business through submarine engines. FM’s unique opposed-piston diesel engine powered about half the U.S. Navy’s World War II submarine fleet and developed a great reputation for reliability; the adaptation to railroad equipment during and after the war seemed like a natural transition.

In the opposed-piston motor, each cylinder had a piston at either end and the combustion chamber in the middle. There were no valves or cylinder heads. Intake and exhaust occurred through holes in the cylinder walls. The upper and lower banks of pistons each powered a separate crankshaft, and the two crankshafts were linked together to power the locomotive. While this sounds like a complex way to build an engine, the OP diesel in fact had several advantages over a conventional motor: less moving parts, terrific acceleration, and about double the horsepower per cylinder.

FM had tooled up to produce its first diesel-electric, a 1000 hp switcher, when World War II intervened, and its entire production of OP engines was requisitioned for submarine service. The War Production Board allowed FM to build one prototype locomotive in 1944, and the H10-44 was born. With a high hood like all subsequent FM locomotives — to clear the tall OP motor — and styling polished by industrial designer Raymond Loewy of Pennsy GG1 fame, the muscular H10-44 made FM a new contender in the nascent diesel locomotive business. In the postwar market, with railroads clamoring for new power to replace their war-weary fleets, FM’s plant worked at capacity filling H10-44 orders from a dozen Class 1 railroads and many short lines as well.


  • Intricately Detailed Durable ABS Body
  • Die-Cast Truck Sides, Pilots and Fuel Tank
  • Metal Chassis
  • Metal Handrails and Horn
  • (2) Handpainted Engineer Cab Figures
  • Authentic Paint Scheme
  • Metal Wheels, Axles and Gears
  • (2) Remote Controlled Proto-Couplers
  • Prototypical Rule 17 Lighting
  • Directionally Controlled Constant voltage LED Headlights
  • Lighted LED Cab Interior Light
  • (2) Precision Flywheel-Equipped Motors
  • Operating ProtoSmoke Diesel Exhaust
  • Onboard DCC/DCS Decoder
  • Locomotive Speed Control In Scale MPH Increments
  • 1:48 Scale Proportions
  • Proto-Sound 3.0 With The Digital Command System Featuring Freight Yard Proto-Effects
  • Unit Measures: 13” x 2 5/8” x 3 3/4”
  • Operates On O-31 Curves

Additional information

cab #

30-21024-1, Cab No. 123, 30-21025-1, Car No. 121


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