Information: - Tunis - Goulette - Marsa or TGM is a 19 km 1,435 mm ( 4 ft 8 1 2 in ) ( standard gauge ) light rail line linking the capital Tunis with La Marsa via La Goulette . - George Stephenson (9 June 1781 12 August 1848) was an English civil engineer and mechanical engineer who built the first public inter-city railway line in the world to use steam locomotives, the Liverpool and Manchester Railway which opened in 1830. Renowned as the "Father of Railways", the Victorians considered him a great example of diligent application and thirst for improvement, with self-help advocate Samuel Smiles particularly praising his achievements. His rail gauge of , sometimes called "Stephenson gauge", is the standard gauge by name and by convention for most of the world's railways. - In rail transport, track gauge is the spacing of the rails on a railway track and is measured between the inner faces of the load-bearing rails. - High-speed rail is a type of rail transport that operates significantly faster than traditional rail traffic, using an integrated system of specialized rolling stock and dedicated tracks. While there is no single standard that applies worldwide, new lines in excess of and existing lines in excess of are widely considered to be high-speed, with some extending the definition to include lower speeds in areas for which these speeds still represent significant improvements. The first such system began operations in Japan in 1964 and was widely known as the bullet train. High-speed trains normally operate on standard gauge tracks of continuously welded rail on grade-separated right-of-way that incorporates a large turning radius in its design. - Tunisia ('; ), officially the Republic of Tunisia (') is the northernmost country in Africa, covering . Its northernmost point, Cape Angela, is the northernmost point on the African continent. It is bordered by Algeria to the west and southwest, Libya to the southeast, and the Mediterranean Sea to the north and east. Tunisia's population was estimated to be just under 11 million in 2014. Tunisia's name is derived from its capital city, Tunis, which is located on Tunisia's northeast coast. - The standard gauge (also Stephenson gauge after George Stephenson, International gauge, or normal gauge) is a widely used railway track gauge. Approximately 55% of the lines in the world are this gauge. All high-speed rail lines (except those in Russia, Uzbekistan, and Finland) are standard gauge. The distance between the inside edges of the rails is defined to be (except in the United States, where it is still defined in Imperial and US customary units as ). It is also called the UIC gauge or UIC track gauge, the European gauge in the EU and Russia, or uniform gauge in Queensland, Australia. - El Marsa (', French: La Marsa) is a coastal town in far north eastern Tunisia near the capital Tunis. The population is estimated as 92,987, as of 2014. The old summer capital of pre-colonial Tunisia, it is today a popular vacation spot for many wealthy Tunisians. It is connected to Tunis by the TGM railway. Gammarth is adjacent to El Marsa further up the coast. - Tunis ("") is both the capital and the largest city of Tunisia. The greater metropolitan area of Tunis, often referred to as "Grand Tunis", has some 2,700,000 inhabitants. - La Goulette ("") is the port of Tunis, the capital of Tunisia. The Kasbah fortress was built in 1535 by Charles I of Spain but was captured by the Ottoman Turks in 1574. La Goulette is located at around . - A kasbah Arabic , or in older English casbah, and qasbah or qassabah in India, is a type of medina, or fortress (citadel). What entity does 'tgm' has the relation 'instance of' with?
Answer:
railway line