In the Kingdom of Prussia, Frederick William III ordered the construction of an experimental line in 1819, but due to the procrastination of defence minister Karl von Hake, nothing happened until 1830 when a short three-station line between Berlin and Potsdam was built. The design was based on the Swedish telegraph with the number of shutters increased to twelve. "Postrat" Carl Pistor proposed instead a semaphore system based on Watson's design in England. An operational line of this design running Berlin-Magdeburg-Dortmund-Köln-Bonn-Koblenz was completed in 1833. The line employed about 200 people, comparable to Sweden, but no network ever developed and no more official lines were built. The line was decommissioned in 1849 in favour of an electrical line.