Letter series (1923–1936) Yellow started its model designation at the end of the alphabet and worked forward. Initially four types were offered: • Z type single-deck bus or coach • Z type
double-deck bus • Y type coach • X type bus or coach. All were conventional
front-engine design vehicles powered by Yellow
Knight I4 sleeve-valve gasoline engines, or a
General Electric gas-electric hybrid unless noted otherwise. The Knight engine was connected to the rear wheels by a mechanical drive shaft. In gas-electric models, a gasoline engine in front supplied electric power to two large electric motors mounted on the rear axle. File:Greyhound Bus Station, Eastern Greyhound Lines (NBY 2186).jpg|thumb|A postcard image (c. 1930) of a Yellow Coach Model Z-250 depicted in the livery of Eastern Greyhound Lines (similar photo)
700-series (1931–1939) File:Model 718 - 41 Passenger - New York City Omnibus Corporation - (3593428904).jpg|right|thumb|Model 718 (NYPL Collection)) File:Greyhound bus (1930s Supercoach) Front View.jpg|right|thumb|700-series Greyhound
Super Coach (1938 photo) (side view) In 1931, Yellow Coach introduced its 700 series buses, featuring one of the first bus designs to mount the engine in the rear. reducing mechanical losses, noise, and weight of a long drive shaft and exhaust running between a front engine and the rear drive and tailpipe. Bus manufacturers in Germany and the United Kingdom would not perfect rear-engine models until the 1950s. Customers did not always prefer rear-engined designs, noting that front engines were easier to access, and placed engine noise and vibration away from passengers and sometimes outside the coach body.
Best-selling transit buses: Models 718 and 728 Notable 700-series versions include models
718 and
728 which were developed for use as urban transit. Model 718 sold 426 units to large transit operators in New York and Los Angeles, becoming the most popular transit bus of the early 1930s. Later model
728 sold 1,189 units to transit operators across 9 variants produced in the late 1930s. Both were exclusively rear-engined.
Greyhound (intercity) buses: Models 719 and 743 For
Greyhound Lines, an operator of
intercity bus service, Yellow Coach developed model
719 in 1936 which introduced the high floor, underfloor luggage storage, a flat front and
streamlined styling. In 1937, model 719 was revised to become model
743 and introduced air conditioning and a diesel engine. Models 719 and 743 were both branded as the
Super Coach by Greyhound, and sales were effectively limited to Greyhound and its affiliates. Greyhound Lines purchased all 1,256 units of model 743 produced between 1937 and 1939.
1200-series (1938–1940) The Model 1200 series was launched in 1938 with the re-designation of Model 739 as Model 1203 for
Public Service Corporation. The 6-model series name ended when three were given new P-series names, and another was given a T-series name. By 1940, Model 1200 series designs were renamed into either the
T- or
P-series. The new model designations indicated type, fuel, propulsion (for transit) or customer (for parlor), seating capacity, and version number. (The first was -01, the second, -02, and so on.)
GM and GMC In 1944, General Motors completed its acquisition and merger of Yellow Coach. The T-Series and P-Series production and series numbering continued under the
GM and GMC bus brands, along with other variants such as B-Series school buses and S-Series suburban buses. Yellow Coach designs would continue to be widely produced until 1959, when GM introduced its
New Look models. The last Yellow Coach design ceased production in 1969. ==See also==