The first generation of the Volkswagen Type 2 with the split windshield, informally called the Microbus, Splittie among modern fans, was produced from 8 March 1950 through the end of the 1967 model year. From 1950 to 1956, the T1  was built in Wolfsburg in 1956, it was built at the completely new Transporter factory in Hanover.
A higher compression ratio became standard in 1955 while an unusual early version of the 30 kW  engine debuted exclusively on the Type 2 in 1959. Any 1959 models that retain that early engine today are rare. Since the engine was discontinued almost immediately, no spare parts were made available.
The early versions of the T1 until 1955 were often called the Barndoor.  And it was called T1 since the 1990s, owing to the enormous rear engine cover, while the later versions with a slightly modified body, smaller engine bay and roadwheels instead of the original 16" ones are nowadays called the T1b. From the 1964 model year when the rear door was made wider the vehicle could be referred to as the T1cc 1964 also saw the introduction of an optional sliding door for the passenger or cargo area instead of the outwardly hinged doors typical of cargo vans.