 To allow deep draft vessels to unload, a rail causeway of approximately seven miles was built out into the Persian Gulf with the first five miles a rock causeway and the last couple of miles a section made of a steel trestle.One of the first vessels to unload was a Dutch freighter, in 1950, with a load of rails for construction of the line.The first trains started moving between Dammam and Riyadh in the early 1950s.