Thomas Marr Johnson
Thomas Marr Johnson (1826-1874)
1874 of Great George-street, Westminster, and 14, Westbourne-street.
1875 Obituary 
MR. THOMAS MARR JOHNSON was born at Appleby, in Lincolnshire, on the 29th of June, 1826.
On leaving school, he was articled for four years to Mr. Dykes, surveyor, of Houghton, Yorkshire, and was afterwards engaged for two years, on his own account, in surveying and other works connected with the Fens of Lincolnshire.
He then entered the office of Mr. John Fowler, Past-President Inst. C.E., with whom he remained until the year 1870.
Mr. Johnson early exhibited great ability and untiring energy, with considerable skill in design, and the closest attention to those details so important to success in engineering matters. He was, therefore, soon intrusted by Mr. Fowler with important works, including the Mid-Kent railway, the Farnborough Extension of the West End and Crystal Palace railway, the River Nene drainage and navigation, and the Norfolk estuary, river, and reclamation works.
Between the years 1860 and 1869, he was, in conjunction with Mr. B. Baker, Assoc. Inst. C.E., exclusively occupied in carrying out, under Mr. Fowler’s instructions, the works of the Metropolitan railway system, with the exception of a few months passed in the United States; and it was during these years that. he developed fully the qualities which especially distinguished him in the professional circle in which he moved. These undertakings involved some of the heaviest and most complicated engineering works of the day.
In February 1870, Mr. Johnson left Mr. Fowler and joined the firm of Messrs. G. Smith and Co.*, builders and contractors. During the partnership, which continued up to the time of his death, this firm executed several large works, amongst others, the new Town Hall at Manchester, and Eaton Hall, Chester, the residence of the Duke of Westminster. He also, in conjunction with Mr. William Mills, M. Inst. C.E., superintended the design and execution of the new Holborn Viaduct Station for the London, Chatham, and Dover Railway Company.
Mr. Johnson was elected an Associate of the Institution of Civil Engineers on the 6th of April, 1852, and was transferred to the rank of Member on the 7th of February, 1863. He was also corresponding member of the American Society of Civil Engineers.
He died on the 20th of July, 1874, at the age of forty-eight.
1874 Obituary 
- Might this be a reference to George Smith and Co (of Pimlico)?