Matthys Michiel Loubser, mechanical engineer, was the son of Jacobus Willem Loubser and his wife Jacoba Anna Christina, born Malan. He received his secondary education at the Jongens Hoërskool (Boys' High School), Stellenbosch, and passed in the first class in the matriculation examination of the University of the Cape of Good Hope in 1906. He continued his studies at Victoria College (from 1918 the University of Stellenbosch) and was awarded the BA degree with honours in applied mathematics by the University of the Cape of Good Hope in 1909. During his student days he was a member of the Victoria College Scientific Society (Thom, 1966, p. 326).
After graduating Loubser went to Germany for further studies at the Technische Hochschule in Berlin-Charlottenburg where he concentrated on railway engineering and qualified as a Diplom Ingenieur (Machinenbau) in 1914. He was prevented from returning to South Africa by being detained as a prisoner of war at the outbreak of World War I (1914-1918), but was granted parole so that he was able to continue to gain practical experience in engineering as a draughtsman. In 1919, shortly before his return to South Africa, he married Marie Klara Hedwig Koschinski, with whom he had two sons.
Back in South Africa Loubser found that academically qualified professional engineers were not yet recognized by the South African Railways. He therefore became a lecturer in physics and applied mathematics at the universities of Stellenbosch, Cape Town and the Witwatersrand for several years. Then, in 1925, he obtained an appointment as test engineer under the chief mechanical engineer of the South African Railways, where he was put in charge of the newly acquired dynamometer carriage and contributed to important improvements to rolling stock and rails. He advanced rapidly in the several branches of railway engineering, including an appointment as locomotive superintendent in Durban in 1934. In 1937 he was appointed as chief mechanical engineer of the South African Railways in Pretoria (at first in an acting capacity, until 1939), a position he held until his retirement in 1949. He was responsible for the design of several modern steam locomotives and for supervising the building of the first local series of locomotives, namely twelve Class S1 shunting engines. Most of his work was written up in the form of internal reports, but some of his more fundamental work led to publications in engineering journals. For example, "Mechanical engineering problems of the 3 ft. 6 in. gauge, SA Railways" (Engineering, 1929), and "Locomotive boiler design: Theory and practice" (Journal of the Institute of Locomotive Engineers, 1938, with E. S. Cox). The latter paper earned him the gold medal of the Institute of Locomotive Engineers. Also, "Design and manufacture in South Africa of the Class S. 1. Locomotive" (Journal of the South African Institute of Engineers, 1948). He had a strong interest in the advancement of technical terminology in Afrikaans and was partly responsible for the compilation of a list of railway terms. He also published a paper in Afrikaans on the theory of the steam locomotive in the Annals of the University of Stellenbosch (1945).
After his retirement Loubser was chairman of the South African Railways Tender Board from 1950 to 1955. He also served on the council of the South African Bureau of Standards and at the time of his death was still working on decimalization problems for the Bureau. He was appointed a member of the Council for Scientific and Industrial Research (CSIR) in 1956 and was a consultant to the firm Dowson and Dobson in Johannesburg until his death.
Loubser was awarded an honorary DSc degree by the University of Stellenbosch in 1942. He received the Havenga prize of the Suid-Afrikaanse Akademie vir Wetenskap en Kuns (SAAWK) in 1951/2. As a former chairman of the engineering division of the SAAWK he represented the Akademie on the first board of management of the Professional Engineers' Joint Council of South Africa in 1961. His friends remembered him as an honorable and uncomplicated person, a true gentleman, always ready to assist others.
