[4] At that time, the only Finnish heavy vehicle producer Oy Suomen Autoteollisuus Ab (SAT) was building a new factory in Karis, a location considered less likely than Helsinki to come under attack from Soviet air raids.

Heavy vehicle importers and some political cliques thought SAT was trying to benefit from the war and to gain a dominant position in the Finnish market.

[4] Defence minister Rudolf Walden called a meeting held on 3 and 4 March 1943 to explore solutions to the acute shortage of vehicles.

It was clear from the start that vehicles should be produced away from Helsinki; the company sought a suitable location close to good rail, road and waterway connections.

After a short and intensive testing period, serial production began on 29 October 1945 but because of a shortage of materials and component quality problems, the first vehicles were not ready until early 1946.

The frustrated component suppliers left the business and the Ministry of Trade and Industry terminated the vehicle supply contract from the end of 1946.

In early 1946, Yhteissisu had agreed with the Ministry of Trade and Industry that vehicles not bought by the state could be sold on the civilian market.

In a general meeting held in 1948, the board decided to rename the company Vanajan Autotehdas and the brand of the vehicles became Vanaja.

[15] General manager Kytölä travelled to France and West Germany in 1947 and early 1948 to buy military surplus materials from the Western Allies.

The White Half-Track vehicles were without armour; Kytölä's idea was to equip them with superstructures for field or forest clearing, or to convert them into Four-wheel drive lorries by replacing the tracks with a conventional rear axle.

[18] Both VAT and SAT were criticised in 1954 by heavy vehicle importers because the two companies had access to a large share of the limited foreign currency reserves for component supply.

The following year, the government started to investigate possibilities for importing heavy vehicles in kit form to reduce foreign-currency expenditure.

These proved to be too inefficient, and the following year the company ordered a batch of 300 stronger Leylands made in the Netherlands by van Doorne's Automobilfabriek N.V.[21] In 1956, VAT became the representative for Ansaldo S.A. and Kämper-Motoren GmbH.

The domestic vehicles performed well in the test; in some cases the rear-wheel driven Sisus and Vanajas outperformed the 4×4-driven foreign competitors.

Due to the AEC engines, the Vanajas did not raise interest among the potential Greek customers, as relations between the UK and Greece were bad at the time.

[19] The enthusiastic engineers listened carefully to every individual customer's wishes and designed vehicles accordingly, with two or three axles, desired layout, wheelbase and with conventional or forward control cabin.

Conventional bus chassis were delivered with bonnet and wings, but the forward control types left the factory without any body parts.

The bus chassis were tested in a similar way; because there was no body, the drivers only had warm clothes and driving goggles to protect them against the weather conditions.

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.

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.

[48] 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.

Most of the public understood the need for the merger of two small companies, which were both operating in a very limited market and trying to challenge the mass producers.

[57] Some customers were upset because the last long-nosed Vanajas were equipped with cabins from Jyry-Sisu; they said they would never buy Sisu and moved to imported vehicles.

The Vanaja LK-series with a large, centrally mounted engine was discontinued, which led to the loss of the main customer, Väinö Paunu Oy.

SAT offered Sisu chassis to replace the Vanaja models, but a number of bus operators, including TKL [fi], rejected them.

Lorry production was gradually concentrated at Karis and Sisu-Hämeenlinna focused on producing mobile cranes, bus chassis, terminal tractors and military vehicles.

[62] Former VAT personnel had to increase production of the new portfolio and simultaneously adopt new processes, so it was three to four years before the Hämeenlinna factory could deliver results in line with its capacity.

[62] Bus chassis production was officially discontinued in 1986,[62] although in 1989 a small batch was made and later fitted with Ajokki coach bodies for delivery to a customer in the Soviet Union.

[69] Vanaja was sometimes characterised as "one of the world's best lorries" because of the company's ability to engineer a vehicle ideal for each application in accordance with the customer's wishes.