King Frederick William IV of Prussia purchased a set of royal coaches in 1857. They ran on two and three axles and were painted in a chestnut brown. None of these have survived. After 30 years of use they became technically outdated, so in 1889 the new emperor, Wilhelm II, who was always very interested in engineering and technological developments started to order new coaches. Until the end of his reign in 1918 there were about 30 coaches. These ran on bogies with either two or three axles and were painted in bright blue and ecru which contrasted significantly with ordinary coaches of the day which usually were painted green, grey or brown; only during World War I the imperial coaches were painted green. The private car of the emperor is on display in the German Museum of Technology, Berlin, the private car of the empress in the museum of former Linke-Hofmann-Busch GmbH (today: Alstom Transport Deutschland GmbH) who built the coach.