This 600 mm gauge line was originally opened for just one year in 1972 . It was part of the of the Floriade, the world horticultural exhibition held in the Netherlands once every ten years. One of the attractions of the new Amstel park was the 3.7-kilometer ring rail line with its two Porsche trains . After Floriade , the trains went back to Germany and both were used in the IGA in 1973 in Hamburg. After a number of years , two trains came back. a light green one, which had already been in Amsterdam, and a green train, probably from the last, Cologne-built series. In 2005-'06 the locomotives were painted in the current ivory white with black hood and top cover.