Fox, Henderson & Co var et engelsk jernbaneentreprenørfirma baseret i Smelthwick ved Birmingham.

Several firms engaged in engineering and metalworking were established in the town in the mid 19th century. The most important in the 1840s and early 1850s was Bramah, Fox & Co., later Fox, Henderson & Co., of the London Works in Cranford Street. The firm was established in 1839 by Charles Fox, an engineer who had acted as one of Robert Stephenson's principal assistants during the construction of the London and Birmingham Railway, and John Joseph Bramah, one of a notable family of engineers and iron-founders. (fn. 1) The partners acquired 5 a. of the Moilliets' Smethwick Grove estate and in 1840 began the erection of their works. (fn. 2) It was apparently in operation by 1841. (fn. 3) Fox, although initially the junior partner, was probably from the first its leading figure; it was he who designed the works and supervised its construction. (fn. 4) By 1845 Bramah had retired from the business, Fox had been joined by John Henderson, a Scottish engineer, and the firm had become Fox, Henderson & Co. (fn. 5) Fox's experience as a railway engineer led him to invent various improvements to railway permanent way, and his firm was the first to produce a virtually complete range of railway plant and stock. There was, however, much other business: products c. 1850 included wrought-iron pipes, steam-engines, boilers, gasometers, and tanks for ships. (fn. 6) Fox, Henderson & Co. became one of the most celebrated firms of civil engineers in the country as a result of its work for Joseph Paxton's Crystal Palace. Fox produced the working drawings for Paxton, who also made a major addition to his original plan at Henderson's suggestion. The firm was the contractor for erecting the palace and made most of its iron work. Fox supervised the construction of the building and was knighted in 1851 for his contribution towards the Exhibition. He and Henderson were also the contractors for the removal of the palace to Sydenham. (fn. 7) Fox and Henderson's experience with William (later Sir William) Siemens, inventor of the regenerative furnace, was less satisfactory. In 1848 Siemens, then a young man, interested the partners in one of his early inventions, a regenerative steam-engine and condenser. The firm employed him and bought patent rights in the invention, and for some five years attempts were made to build engines to Siemens's specifications. None was successful. Siemens himself profited greatly from his years at the London Works; Fox and Henderson, however, began to recoup their losses only when he persuaded them to interest themselves in the electric-telegraph equipment patented by his brother Werner, thereby helping them to win large telegraph contracts. (fn. 8)

In 1850 the London Works was described as 'the finest and most compact range of [industrial] buildings in South Staffordshire'. It had been expanded to form a hollow square, in the centre of which stood the boiler-house with its two 75 h.p. engines. The smiths' shop contained 70 forges and was stated to be the largest in the world. The firm was then producing about 300 tons of castings a week and usually had between 800 and 1,200 men working at Smethwick. At the height of its success it was the town's principal employer of labour, and when it failed in 1856 some 2,000 people were thrown out of work. (fn. 9) The crash apparently came because it could not obtain payment for one of its numerous foreign contracts. Its creditors attempted to keep the works going but were unsuccessful. (fn. 10)