San Marino is a small European republic, with limited public transport facilities. It is an enclave in central Italy. The principal public transport links involve buses, helicopters, and an aerial tramway. There was a public electric railway network, a small part of which has been preserved and returned to service in 2012 as a tourist attraction. Railway There is a disused railway to Rimini, with much of the infrastructure such as tunnels still intact. An 800-metre section from just outside the San Marino terminal station was put into service in 2012 as a tourist attraction. Aerial tramway There is a 300 m aerial tramway connecting the city of San Marino on top of Monte Titano with Borgo Maggiore, a major town in the republic, with the second largest population of any Sammarinese settlement. Indeed, for the tourist visitor the aerial tramway gives the best available views of Borgo Maggiore, as the cars sweep low over the rooftops of the main town square. From here a further connection is available to the nation's largest settlement, Dogana, by means of local bus service. Two aerial tramway cars, known as gondolas, and numbered '1' and '2', operate in opposition on a cable, and a service is provided at roughly fifteen-minute intervals throughout the day. A third vehicle is available on the system, being a service car for the use of engineers maintaining the tramway. The upper station of the aerial tramway serves no other purpose (although it is situated close to a tourist information office). However, the lower station in Borgo Maggiore has a number of retail and catering outlets situated within its overall structure. Taxi and private road vehicles There are 220 km of highways in the country, the main road being the San Marino Highway. Roads are well used by private car drivers. Sammarinese authorities license private vehicles with distinctive licence plates which are white with blue figures, usually a letter followed by up to four numbers. To the left of these figures is printed the national Coat of Arms of San Marino. Many vehicles also carry the international vehicle identification code (in black on a white oval sticker), which is "RSM". Since 2004 custom licence plates have also become available. A limited licensed taxi service operates nationwide. There are seven licensed taxi operating companies in the republic, and Italian taxis regularly operate within San Marino when carrying passengers picked up