page_title: Vanajan Autotehdas
section_title: Bus chassis production
hierarchical_section_title: Vanajan Autotehdas / Bus chassis production
caption_attribution_description: Suomi: Vanaja VAT-4800 rear engined bus from 1956. Coachwork by K. Nummela Oy.
context_page_description: Vanajan Autotehdas Oy was a producer of heavy vehicles based in Hämeenlinna, Finland. The company was founded as Yhteissisu Oy in 1943 by the Finnish government and a number of major Finnish companies with the aim of producing lorries and buses for the Finnish Defence Forces. World War II was over before the company could start series production; it was renamed Vanajan Autotehdas and the marque became Vanaja. Subsequently, the production consisted of outdated lorry models, partly built from military surplus materials. After overcoming initial difficulties, the company modernised its products, became profitable and grew until the mid-1950s. Many major components, including engines, were imported. Diesel engines became widely available in 1955, and in 1959 VAT introduced its most significant innovation, the full load lifting tandem axle mechanism, which improved off-road capability significantly; the system is now used in Sisu vehicles.
  The company started producing bus chassis in 1950, and the superstructures were built by a number of Finnish coach builders. The last models were appreciated by a number of bus operators, and missed after production was stopped.
context_section_description: Bus chassis production began in 1950. VAT made the first prototypes of rear-engined buses in 1956. The company made two prototype chassis, which were designated model VAT-4800; the superstructures were made by coach builders Ajokki Oy and Nummela Oy. The solution caused several technical problems, including proper cooling and transfer of heating to the front end of the body. The cooling problem was finally solved by a large air scoop located at the back of the roof; this was not regarded as an aesthetically pleasing arrangement. As the solution was found, VAT produced ten more rear-engined chassis called type VAT-5200.
  By 1958, all VAT bus chassis were equipped with air brakes; later these were also fitted to lorries. The decision was influenced by one of the worst road traffic accidents to happen in Finland; 15 people drowned in Konnevesi when a fairly new Vanaja bus drove through the boom barrier of a ferry slip, sinking in 4 metres (13 ft) of water. The driver survived and said the bus' brakes had failed; this was confirmed in the following investigation, which found the sealing of one of the hydraulic Lockheed brakes had failed.
  VAT delivered its first mid-engined bus chassis to Ajokki Oy coach works in April 1958. It was powered by a horizontally mounted 164-hp AEC diesel engine. The end customer was bus operator Väinö Paunu Oy, which also participated in the development work. In 1960, VAT introduced the VLK500 chassis with air suspension and dual-circuit air brakes. VAT returned to building rear-engined buses in 1966–67, but sales did not reach the level of the mid- and front-engined models. The company conducted a number of experiments with the construction; one example was a bus with a frameless structure in which the beams were replaced by a lighter solution.
caption: A Vanaja VAT-4800 with Nummela coachwork from 1956. Note the engine air intake scoop on the roof.
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