----After World War I, industrialization hit full stride in America, especially in the manufactured goods sector. For railroads, this meant that the era of slow drag freight, with the exception of mineral and coal hauling, was giving way to a new age of fast freight. As the factory assembly line system evolved, freight schedules became as time-conscious as the swiftest passenger varnish. Passenger consists themselves became heavier as steel-sided cars replaced those made of wood, often requiring helper locomotives when faced with any degree of grade. In the ‘teens, the American Locomotive Company developed the 4-8-2 wheel arrangement, dubbed the Mountain type, to keep fast passenger service on track. The Pennsylvania Railroad would later take the Mountain type steam locomotive to the pinnacle of its capability.
 ----In 1923, the Pennsylvania Railroad sought a dual-purpose locomotive to handle both fast freight and fast passenger service. Unlike their later, marginally successful experiments with turbines and duplex drives, the railroad bega with standard parts from existing locomotives placed on the 4-8-2 platform, producing a design so perfect that it was one of the very last classes of steamers retired from Pennsy rails. The Pennsylvania M1 began with an I1s 2-10-0 boiler including an enlarged combustion chamber. The cylinders came from an L1s 2-8-2. The 110-P-75 tender was the same type used behind the K4 4-6-2. A controversial part of the design involved the 72-inch drivers taken from the G5 4-6-0. Most experts considered them too large for freight service and too small for passenger service. After years of rigorous testing, the critics were silenced. The Pennsylvania Railroad ordered the first 200 M1 locomotives in 1926.
 ----These Mountains were so successful that the railroad ordered 100 more locomotives in 1930. The order was spread between three builders: Baldwin, the Altoona Works and Lima. The 1930 class was dubbed M1a. The prototype for the Lionel M1a is number 6759, built by the Pennsy’s own Altoona Works. Our model accurately reflects the improvements added to the M1a: dual air compressors, Worthington feedwater heater, mechanical lubricator, and possibly the greatest improvement, a 210-F-75 “coast-to-coast” tender. Our rendition of the 6759 features this extra-large tender with riveted sides, a wood detailed brakeman’s doghouse and separately applied classification plaque. The larger tender was a relief to train crews, as the original 11,980 gallon, 18- ton capacity M1 tender was hardly a match for a locomotive that consumed five tons of coal per hour.
 ----The M1’s massive consumption translated into over 4000 horsepower. Although clearance restrictions and expanding electrified rail service meant that only a handful of M-class locomotives hauled passenger consists, they did single-handedly haul the heaviest Limiteds over the Alleghenies from Harrisburg to Pittsburgh. More importantly to the Pennsy’s bottom line, they had an immediate impact on freight business. In 1925 before the M1’s entered service, net-tons-per-train hour was 19,706 tons. By 1931, with all 300 members of the M-class on the roster, the statistic rose to 30,987 tons.
 ----In 1939, 6759 had her finest moment, displayed at the 1939 New York World’s Fair. The scale-sized Lionel M1a appears as she did during the 1930s into the 1940s, before the infamous Pennsy “facelifts” which dropped the generator across the smokebox and favored a solid drop coupler pilot. Many thought that these changes, although they increased serviceability, marred the classic look of the locomotives.
 ----The Lionel M1a includes the unobstructed smokebox and slatted pilot of the earlier locomotives. Like all of the M-class Mountains, 6759 received a passenger service chime whistle. The newly enhanced RailSounds sound system accurately reproduces this distinctive cry along with the spectacular chuffs and hisses of “Pennsy’s best” coming to life.