Germany's first railway ran just six kilometres.
On 7 December 1835, the locomotive "Adler" pulled the first train from Nuremberg to Fürth: about 6 kilometres in roughly 9 minutes. Engine and driver came from Stephenson's works in England. On many days the line even ran with horses, because coal was expensive. Still, this was the start of a network exceeding 50,000 kilometres by 1900.
Useful: A prototype doesn't need to be big; it needs to prove the idea holds.
Source: de.wikipedia.org