Mini-shinkansen (ミニ新幹線?) is the name given to the routes where former narrow gauge lines have been converted to standard gauge to allow Shinkansen trains to travel to cities without the expense of constructing full Shinkansen standard lines. Two mini-shinkansen routes have been constructed: the Yamagata Shinkansen and Akita Shinkansen. Shinkansen services to these lines traverse the Tohoku Shinkansen line from Tokyo before branching off to traditional main lines. On both the Yamagata/Shinjo and Akita lines, prior to conversion the lines were dual track mainlines. One of the original narrow gauge lines has been regauged, resulting in parallel bi-directional narrow and standard gauge lines now being in service. In some sections the narrow gauge line is dual gauge, providing the opportunity for Shinkansen services to pass each other without stopping. The maximum speed on these lines is 130 km/h, however the overall travel time to/from Tokyo is improved due to the elimination of the need for passengers to change trains at Fukushima and Morioka respectively. As the Loading gauge (size of the train that can travel on a line) was not altered when the rail gauge was widened, only Shinkansen trains specially built for these routes can travel on the lines. At present they are the E3 and E6 series trains. Whilst no further Mini-shinkansen routes have been proposed to date, it remains an option for providing Shinkansen services to cities on the narrow gauge network.