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AA was a designator used for several different diesel locomotive types custom built by General Motors Corporation EMC/GM with passenger or baggage space in the same body. This locomotive is listed as class AA-6 [1] by R. Craig, and the designation is logical as the locomotive is described as "half an E6" in the Second Diesel Spotter's Guide. [2]
A diesel locomotive is a type of railway locomotive in which the prime mover is a diesel engine. Several types of diesel locomotive have been developed, differing mainly in the means by which mechanical power is conveyed to the driving wheels.
One such was a single locomotive built for the Missouri Pacific Railroad, delivered in August 1940, numbered #7100. MP 7100 was built for service with the Delta Eagle passenger train, which ran between Memphis, Tennessee and Tallulah, Louisiana. Note: Missouri Pacific ordered all their 'E' units with portholes instead of square windows like most of the E series from the EA to E7's. This was the only MoPac unit with square windows (on the baggage door).
The Missouri Pacific Railroad, commonly abbreviated as MoPac and nicknamed The Mop, was one of the first railroads in the United States west of the Mississippi River. MoPac was a Class I railroad growing from dozens of predecessors and mergers, including the St. Louis, Iron Mountain and Southern Railway (SLIMS), Texas and Pacific Railway (TP), Chicago and Eastern Illinois Railroad (C&EI), St. Louis, Brownsville and Mexico Railway (SLBM), Kansas, Oklahoma and Gulf Railway (KO&G), Midland Valley Railroad (MV), San Antonio, Uvalde and Gulf Railroad (SAU&G), Gulf Coast Lines (GC), International-Great Northern Railroad (IGN), New Orleans, Texas and Mexico Railway (NOTM), Missouri-Illinois Railroad (MI), as well as the small Central Branch Railway, and joint ventures such as the Alton and Southern Railroad (AS).
Memphis is a city located along the Mississippi River in southwestern Shelby County, Tennessee, United States. The 2017 city population was 652,236, making Memphis the largest city on the Mississippi River, the second most populous city in Tennessee, as well as the 25th largest city in the United States. Greater Memphis is the 42nd largest metropolitan area in the United States, with a population of 1,348,260 in 2017. The city is the anchor of West Tennessee and the greater Mid-South region, which includes portions of neighboring Arkansas and Mississippi. Memphis is the seat of Shelby County, the most populous county in Tennessee. As one of the most historic and cultural cities of the southern United States, the city features a wide variety of landscapes and distinct neighborhoods.
Tallulah is a small city in and the parish seat of Madison Parish in northeastern Louisiana, United States. The 2010 population was 7,335, a decrease of 1,854, or 20.2 percent, from the 9,189 recorded at the 2000 census.
Since the two-car train the unit would have to haul was comparatively light, the AA was built with only one 1,000 hp EMD 567 V12 prime mover, and a baggage compartment where the second diesel would have been.
A V12 engine is a V engine with 12 cylinders mounted on the crankcase in two banks of six cylinders each, usually but not always at a 60° angle to each other, with all 12 pistons driving a common crankshaft. Since each cylinder bank is essentially a straight-six which is by itself in both primary and secondary balance, a V12 inherits perfect primary and secondary balance no matter which V angle is used, and therefore it needs no balance shafts. A four-stroke 12 cylinder engine has an even firing order if cylinders fire every 60° of crankshaft rotation, so a V12 with cylinder banks at 60° or 180° will have even firing intervals without using split crankpins. By using split crankpins or ignoring minor vibrations, any V angle is possible. The 180° configuration is usually referred to as a "flat-twelve engine" or a "boxer" although it is in reality a 180° V since the pistons can and normally do use shared crankpins. It may also be written as "V-12", although this is less common.
In engineering, a prime mover is an engine that converts fuel to useful work. In locomotives, the prime mover is thus the source of power for its propulsion. In an engine-generator set, the engine is the prime mover, as distinct from the generator.
Other EMC/GM locomotives carrying the AA classification include the Pioneer Zephyr, Flying Yankee, and General Pershing Zephyr power units.
The Pioneer Zephyr is a diesel-powered trainset built by the Budd Company in 1934 for the Chicago, Burlington and Quincy Railroad (CB&Q), commonly known as the Burlington Route. The trainset was the second internal combustion powered streamliner built for mainline service in the United States, the first such train powered by a diesel engine, and the first to enter revenue service. The trainset consists of one power/RPO car, one baggage/buffet/coach car, and one coach/observation car. The cars are made of stainless steel, permanently articulated together with Jacobs bogies. The construction incorporated recent advances such as shotwelding to join the stainless steel, and unibody construction and articulation to reduce weight. It was the first of nine similarly built trainsets made for Burlington and its technologies were pivotal in the subsequent dieselization of passenger rail service. Its operating economy, speed, and public appeal demonstrated the potential for diesel-electric powered trains to revitalize and restore profitability to passenger rail service that had suffered a catastrophic loss of business with the Great Depression. Originally named the Burlington Zephyr during its demonstration period, it became the Pioneer Zephyr as Burlington expanded its fleet of Zephyr trainsets.
The Flying Yankee was a diesel-electric streamliner built in 1935 for the Maine Central Railroad and the Boston and Maine Railroad by Budd Company and with mechanical and electrical equipment from Electro-Motive Corporation. It was also the name of a passenger train, the third streamliner train in North America after the Union Pacific Railroad's M-10000 and the Chicago, Burlington and Quincy Railroad's Pioneer Zephyr; the Flying Yankee was, in fact, a virtual clone of the latter, except that it dispensed with the baggage/mail space to seat 142 in three articulated cars.
The General Pershing Zephyr was the ninth of the Chicago, Burlington and Quincy Railroad's Zephyr streamliners, and the last built as an integrated streamliner rather than a train hauled by an EMD E-unit diesel locomotive. It was constructed in 1939 with bodywork and passenger cars by Budd Company and diesel engine, electric transmission, power truck, and other locomotive equipment by General Motors Electro-Motive Corporation. Because its intended Kansas City, Missouri to St. Louis, Missouri route passed near the birthplace and boyhood home of famous World War I General John J. Pershing, the train was named after him. The power car was named Silver Charger, after Pershing's horse Charger, while the passenger cars were named after U.S. Army badges of rank—Silver Leaf, Silver Eagle, and Silver Star.
