Letter series (1923–1936)
Yellow started its model designation at the end of the alphabet and worked forward. Initially four types were offered: 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.[12]
- Z type single-deck bus or coach
- Z type double-deck bus
- Y type coach
- X type bus or coach.
700-series (1931–1939)
In 1931, Yellow Coach introduced its 700 series buses, featuring one of the first bus designs to mount the engine in the rear.[1] Mounting the engine in the rear represented a significant innovation,[1][13] reducing mechanical losses, noise, and weight of a long drive shaft and exhaust running between a front engine and the rear drive and tailpipe.[14] Bus manufacturers in Germany and the United Kingdom would not perfect rear-engine models until the 1950s.[13][15] 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.[1] Eventually, the 700 series included both front- and rear-engined models.
In 1934, Dwight Austin, patent-holder on an innovative rear-drive system, was hired by Yellow Coach and soon developed new models in the 700-series with transverse engines and a “V” angle drive. The V-drive and other innovations introduced in the 700 series would become long-lasting standards: air conditioning, diesel engines, a flat front, a high passenger floor (with luggage beneath), and unibody construction. The V-drive would be GM's standard configuration until the 1980s.[16]
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.[17] 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.[17][16]
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.[17] 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.[17][16]
700 Series production details
All models are 96 in wide single-deck buses, except as noted.[18]
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.[23]
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.)[23]
T-series (1940–1942)
All "T"-series models were urban transit buses. The model designation consisted of two or three letters followed by four numbers. These gave a basic description of the type of bus:
All models were rear-engined except the 21xx and 24xx series.
P-series (1939–1944)
The "P" indicated that, as parlor coaches, the P-series was primarily designed for the seated comfort of intercity bus passengers.[23] All models are 96 in wide rear-engine parlor coaches.[29][30][31]
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.[9]
