Robert was born in Willington Quay, Northumberland, to George and Frances née Henderson, before they moved to Killingworth, where Robert was taught at the local village school. Robert attended the middle-class Percy Street Academy in Newcastle and at the age of fifteen was apprenticed to the mining engineer Nicholas Wood. He left before he had completed his three years to help his father survey the Stockton and Darlington Railway. Robert spent six months at Edinburgh University before working for three years as a mining engineer in Colombia. When he returned his father was building the Liverpool and Manchester Railway, and Robert developed the steam locomotive Rocket that won the Rainhill Trials in 1829. He was appointed chief engineer of the London and Birmingham Railway in 1833 with a salary of £1,500 per annum. By 1850 Robert had been involved in the construction of a third of the country's railway system. He designed the High Level Bridge and Royal Border Bridge on the East Coast Main Line. With Eaton Hodgkinson and William Fairbairn he developed wrought-iron tubular bridges, such as the Britannia Bridge in Wales, a design he would later use for the Victoria Bridge in Montreal, for many years the longest bridge in the world. He eventually worked on 160 commissions from 60 companies, building railways in other countries such as Belgium, Norway, Egypt and France.
In 1829 Robert married Frances Sanderson who died in 1842; the couple had no children and he did not remarry. In 1847 he was elected Member of Parliament for Whitby, and held the seat until his death. Although Robert declined a British knighthood, he was decorated in Belgium with the Knight of the Order of Leopold, in France with the Knight of the Legion of Honour and in Norway with the Knight Grand Cross of the order of St. Olaf. He was elected a Fellow of the Royal Society (FRS) in 1849. He served as President of the Institution of Mechanical Engineers and Institution of Civil Engineers. Robert's death was widely mourned, and his funeral cortège was given permission by Queen Victoria to pass through Hyde Park, an honour previously reserved for royalty. He is buried in Westminster Abbey.
Robert Stephenson was born on 16 October 1803, at Willington Quay, east of Newcastle upon Tyne, to George Stephenson and Frances née Henderson, usually known as Fanny. She was twelve years older than George, and when they met was working as a servant where George was lodging. After marriage George and Fanny lived in an upper room of a cottage; George worked as a brakesman on the stationary winding engine on the Quay, and in his spare time cleaned and mended clocks and repaired shoes. Fanny was suffering from tuberculosis (known at the time as consumption), so George would take care of his son in the evening. Robert later recalled how he would sit on his father's left knee with his right arm wrapped around him while he watched him work or read books; his biographer Jeaffreson explained this is why Robert's left arm was the stronger. In autumn 1804 George became a brakesman at the West Moor Pit and the family moved to two rooms in a cottage at Killingworth. On 13 July 1805 Fanny gave birth to a daughter who lived for only three weeks, Fanny's health deteriorated and she died on 14 May 1806.
George employed a housekeeper to look after his son and went away for three months to look after a Watt engine in Montrose, Scotland. He returned to find his housekeeper had married his brother Robert. He moved back into the cottage with his son and briefly employed another housekeeper before his sister Eleanor moved in. Known to Robert as Aunt Nelly, Eleanor had been engaged to be married before travelling to London to work in domestic service. However, returning to get married Eleanor's ship was delayed by poor winds and she arrived to find her fiancé had already married. Eleanor attended the local Methodist church, whereas George would not regularly attend church, preferring on Sundays to work on engineering problems and meet his friends.
Robert was first sent to a village school 1 1⁄2 miles (2.4 km) away in Long Benton, where he was taught by Thomas (Tommy) Rutter. On his way to school, he would carry picks to the smith's at Long Benton to be sharpened. George was promoted in 1812 to be enginewright at Killingworth Colliery with a salary of £100 per annum. He built his first steam locomotive, Blücher, in 1814 and the following year was earning £200 per annum. George had received little formal education but was determined that his son would have one, and so sent the eleven-year-old Robert to be taught by John Bruce at the Percy Street Academy in Newcastle. Most of the children came from middle-class families, and it was while he was at the academy that Robert lost most of his Northumberland accent. At first Robert walked the 10 miles (16 km), but was liable to catch a cold; George fearing tuberculosis bought him a donkey. Robert became a member of the Newcastle Literary and Philosophical Society and borrowed books for him and his father to read. In the evening he would work with George on designs for steam engines. In 1816 they made a sundial together, which is still in place above the cottage door.