de Transports de l'Agglomération Nancienne, or STAN. With two articulation points and a total length of , GLT vehicles are shorter than most modern trams, but long compared with conventional buses. They are designed to look like trams, but they are unidirectional and have bus-like rear-view mirrors. They have 100% low floors, have 40 seats, and have standing room for as many as 105 passengers. In Caen, where the central guidance rail has been installed on all sections of the passenger-service route, the vehicles collect their power from a pantograph, returning it through the central guidance rail, and use their diesel engines and steering wheels only while travelling to and from the depot. Use of a pantograph effectively requires that a surface guidance system be used, to ensure the vehicle remains approximately centred below the overhead wire, so that its pantograph does not slip out from underneath the wire. The Caen vehicles thus cannot move laterally away from the overhead wire except when running in diesel mode (as conventional buses), and for this reason the Caen route is not commonly considered to be a trolleybus system. Nancy's fleet of 25 GLT vehicles use dual trolley poles to collect and return their electric power, in order to allow the use of existing wires constructed for use by the town's previous generation of trolleybuses and to permit operation, where desired by the transport authority, away from the guide rail. The Nancy vehicles follow a guidance rail on about 60% of the route, and thus the Nancy route uniquely is considered to be both a rubber-tyred tramway and a trolleybus line. The system was first brought into use for passenger service in February 2001, but operation was suspended from March 2001 through March 2002 while Bombardier performed upgrades to the vehicles. In Caen, the GLT fleet began operation in November 2002, incorporating the changes made to Nancy's vehicles during the upgrade. They were operated by the Compagnie des Transports de l'Agglomération Caennaise under the name Twisto until 2017, when the system was shut down and replaced by a conventional tram system. Advantages While the GLT's central guidance rail is not significantly less expensive than the rails needed by regular trams, the overall system can be installed at a lower cost since existing trolleybus wires can be used without the installation of tracks, and not all new sections need have either rails or electric