John Mervyn Wrench
John Mervyn Wrench (1849-1903)
1903 Obituary 
JOHN MERVYN WRENCH, the third son of the Rev. T. W. Wrench of St. Michael's, Cornhill, London, was born on 14th November 1849, and received his early education at the Charterhouse School.
In 1866 he entered the Great Western Railway Works at Swindon, as a pupil of Mr. Joseph Armstrong, locomotive superintendent, and in October, 1868, became a pupil of Mr. W. J. Kingsbury, of Westminster.
He became assistant to Mr. C. F. de Kierzkowski Steuart in January, 1871, and in December of the same year was appointed Chief Assistant to the Public Works Construction Co. of Cannon Street,: London, under Mr. de Kierzkowski Steuart, Chief Engineer to the Company, and remained with them for about two years, designing bridge, roof, and general ironwork, rolling stock, etc., and supervising the equipment in England of the East Argentine, Rio Cuarto, Andino, and other foreign railways.
In October 1873, Mr. Wrench was appointed personal assistant to Mr. Charles Stone, chief engineer of the Scinde, Punjab, and Delhi Railway, at Lahore, India, and later acted as resident engineer on various railway extensions.
In India he early distinguished himself by suggesting the utilization of worn-out rails from the permanent way to form girders for building small bridges, whereby a great saving was effected.
He joined the staff of the Indian Midland Railway during the construction of that line in 1884 as assistant engineer, and was promoted to be chief engineer in 1887 shortly after the line was opened for traffic. Whilst with this company he carried out various extensions and improvements, and designed several long viaducts, in building which he made a further use of old rails as temporary scaffolding for the erection of the piers and long girders.
On the amalgamation of the Midland Railway with the Great Indian Peninsular Railway in 1902, he was appointed chief engineer of the combined systems and moved his headquarters from Jhansi to Bombay.
He brought out many inventions connected with his profession, among the best known being the system of interlocking points wills signals known as " Wrench's Interlock."
His death took place from bronchitis from which ho had suffered for some time at his residence, Pali Hill, Bandra, Bombay, on 22nd January 1903, at the age of fifty-three.
He became a Member of this Institution in 1881.
1903 Obituary 
. . . . . In October, 1873, Mr. Wrench was appointed personal Assistant to Charles Stone, then Chief Engineer of the Scinde, Punjab and Delhi Railway, at Lahore, and four years later he was promoted to be a Resident Engineer in the Company’s service. In India he early distinguished himself by suggesting the utilization of worn out rails from the permanent way to form girders for small bridges, whereby a great saving was effected.
Mr. Wrench joined the staff of the Indian Midland Railway during the construction of that line in 1884 as Assistant Engineer and was promoted to be Chief Engineer in 1887 shortly after the line was opened for traffic. . . . [more]