The Tribhuvan International Airport in Kathmandu welcomes visitors into the country and an additional 47 airports make getting around Nepal relatively easy, despite its rugged and mountainous terrain that makes some of the more remote virtually impossible to reach by road. Nepal Airlines is the official air carrier of the country, with a fleet consisting of two Boeing B-757s and seven DHC-6 Twin Otter aircraft. The railway network in Nepal is rather sparse, with the main line running between Janakpur and Jainagar, a town close to the border of India. A rail link between Nepal and Lhasa in Tibet, China is under consideration for future development.