Marcus Smith, civil engineer, started his professional career as a land surveyor. For six years he was employed in the detailed mapping of townships and parishes in various counties of England, under Captain R.K. Dawson of the Royal Engineers. Thereafter he settled in the city of Worcester and was engaged in railway construction and other engineering works. In 1844 he made surveys and plans of a considerable section of the proposed broad gauge Oxford, Worcester and Wolverhampton Railway. The next year he entered into partnership with a Mr Herbert as a firm of engineers and surveyors and during the railway boom of the next few years their firm made surveys and plans for seven sections of railway with a total length of some 370 km. In 1848 he sold his practice and went to France to work on a railway for a British company, but the unsettled state of the country prevented the work from being carried out. The next year he went to the United States where he surveyed and mapped several towns, including Newark, New Jersey. This work led to two publications, Map of the city of Hartford, Connecticut (New York, 1850) and Map of Springfield, Massachusetts (with H.A. Jones, New York, 1851). He proceeded to Canada in 1850, where he surveyed several towns along the proposed route of the Great Western Railway. In March 1852 he was engaged as an engineer on the Great Western Railway and a year later became resident chief engineer of the Hamilton and Toronto Railway. After its completion in 1855 he was engaged on other railway projects until 1860, when he returned to England.
Having obtained a position with the firm contracted to build the Cape Town to Wellington railway in the Cape Colony, Smith left England in September 1860, arriving in Cape Town on 14 October. Much of his work consisted of settling disputes between the company's engineer and the contractor. In 1862 he surveyed a branch line of some 70 km from this railway to Malmesbury for the government, complete with plans, profiles and estimate of the cost of construction. Meanwhile he had been appointed chief engineer for the construction by a private firm of a short suburban railway from Cape Town to Wynberg. His wife and two children, who had remained behind in Canada, joined him in Cape Town in August 1862. Two further children were born at the Cape. In addition to his duties on the railways he did much other work and was often called to give evidence before the select committee on railways. The Wynberg railway was opened for traffic on 17 December 1864, though much remained to be done, while the complete Cape Town to Wellington railway was opened in June 1865. Having completed all his projects and with little prospect of other large engineering works he and his family left the Cape in October 1865, having spent the happiest period of their lives there. The manuscript of his diary covering his stay at the Cape (1860-1866) is in the Strange Collection of the Johannesburg Public Library.
Smith was elected an associate member of the (British) Institution of Civil Engineers in 1866, and subsequently became a full member. After further work on railways in England he again went to Canada in 1868. There he played an important role in the construction of the Intercolonial Railway until 1872, when he was appointed deputy to the engineer-in-chief of the Canadian Pacific Railway. With a staff of assistants he was sent to do the surveys in British Columbia, which were completed during the first half of 1876. From May 1876 to the end of 1878 he was acting engineer-in-chief. He remained with the Canadian Pacific Railway until the end of 1886. Thereafter, as a consultant engineer, he was employed in office work by the Canadian government and stationed in Ottawa, where he inspected and checked the plans of steel and iron railway bridges being constructed all over Canada. He was finally informed that his services were no longer required at the end of 1892, when he was 78. Some years later he was still active, publishing a Report on the Montreal, Ottawa and Georgian Bay Canal... (Ottawa, 1895, 26p).