Boyle, Richard Vicars (1822–1908), civil engineer, was born 14 March 1822 in Dublin, third son of Vicars Armstrong Boyle, a descendant of settlers from Ayrshire, Scotland, who had migrated to Ulster in the seventeenth century, and his wife Sophia, daughter of David Courtney of Dublin. Educated privately, he worked on the trigonometrical survey of Ireland for two years before becoming an apprentice to Charles Blacker Vignoles (qv), the noted engineer. On the completion of his apprenticeship, he was employed as assistant to William Dargan (qv) and worked on the Belfast–Armagh and Dublin–Drogheda railways. In 1845 he was employed in survey duties on the Great Southern & Western Railway, working under Sir John Benjamin MacNeill (qv), and in 1846 was appointed chief engineer on the Longford–Sligo line.
In 1852 he took up an appointment in Spain as assistant to George Willoughby Hemans, son of the poet Felicia Hemans, and together they surveyed and laid out a series of railways and waterworks. Appointed as a district engineer for the East Indian Railway in 1853, he began a series of railway surveys on the subcontinent, was elected as an associate of the Institution of Civil Engineers (January 1854), and subsequently became a member of the ICE (1860). In 1857 he was based at Arrah in the Shahabad district. After the outbreak of sepoy mutinies in Meerut and Delhi, he supervised the evacuation of the women and children of the station to Dinapore. He returned to Arrah and was one of a dozen or so Europeans who decided to remain with the district judge there. During the next few weeks he took part in patrols in an attempt to maintain order in the town. Frustrated at the failure of the district judge to organise proper defences, he obtained cartloads of bricks and, on his own initiative, fortified a small outbuilding in the grounds of his own house, which he had originally intended to use as his billiard-room and library. Bricking up the arches and windows of the small two-storey building, he laid in a quantity of supplies, and when the sepoys at Dinapore mutinied in July the remaining Europeans at Arrah decided to take refuge in this miniature fort. A tiny force of nine Europeans, six Eurasians, and the local Indian deputy-collector remained to face the onslaught of the sepoy rebellion. To their great good fortune they were joined by a troop of fifty Sikh mounted policemen who had been escorting money from Patna, and these men played a crucial role in the defence at Arrah.
On 26 July 1857 a force of some 3,000 sepoys arrived in Arrah and, after releasing the prisoners from the gaol and looting the treasury, they attacked the fortified refuge of Boyle and his companions on the morning of 27 July. During the course of the siege the sepoys brought forward four-pounder field guns, but these made little impact on the defences prepared by Boyle. They also tried to undermine the defences, but their efforts were foiled by the Sikh defenders, who sallied out to capture the sepoys' mining tools. Boyle played a prominent part in the defence; a good marksman, he often climbed on to the roof of the building so that he could fire at the rebel artillerymen. On the evening of 3 August the rebels moved off due to the arrival of a relieving force under the command of Maj. (later Sir) Vincent Eyre. Only one defender had been seriously wounded, a Sikh trooper who later died of his wounds. While Boyle's preparations undoubtedly improved the defenders' chances of survival, he later admitted that the affair would not have ended so well but for the arrival of the Sikh policemen under the command of the redoubtable Jemadar Houken Singh.
Boyle was appointed as field-engineer to Eyre's force but was disabled by a kick from a horse and invalided to Calcutta. Awarded the Indian Mutiny Medal and a grant of land near Arrah for his services, he returned to his duties with the East India Railway. In 1858 he published Indian mutiny: brief narrative of the defence of the Arrah garrison, written by one of the besieged party. He resigned from the East India Railway in 1868 and briefly served as executive engineer of the government of India's public works department before returning to England. In 1869 he was made a companion of the Order of the Star of India. Appointed as engineer-in-chief of the Imperial Japanese Railway in 1872, he became a member of the Institution of Electrical Engineers in 1874. He surveyed main and branch lines for the new Japanese railway before retiring in 1877. In 1882 he presented a paper to the ICE on the Rokugo river bridge in Japan, which was published in Proceedings of the Institution of Civil Engineers. He spent much of the rest of his life travelling and died at his London residence, 3 Stanhope Terrace, Hyde Park, on 3 January 1908. He was buried in Kensal Green cemetery.
He married (1853) Eléonore Anne, daughter of W. Hack of Dieppe, who survived him. They had one son who died in infancy. There is a collection of his letters in the Oriental and India Office collection in the BL.