Francis William Webb (21 May 1836 – 4 June 1906) was an English railway engineer, responsible for the design and manufacture of locomotives for the London and North Western Railway (LNWR). As the LNWR's chief mechanical engineer, he also exercised great influence in political and public life in the Cheshire town of Crewe, once being described as the 'King of Crewe'.

Webb was born in Tixall Rectory, near Stafford, the second son of William Webb, Rector of Tixall.

Showing early interest in mechanical engineering, on 11 August 1851 at the age of fifteen he was articled as a pupil of Francis Trevithick at Crewe Works. Webb joined the drawing office in 1856, at the end of his training. He became Chief Draughtsman on 1 March 1859. On 1 September 1861 he was appointed Works Manager at Crewe and Chief Assistant to John Ramsbottom. Whilst Works Manager, Webb was responsible for the installation of Bessemer converters and the start of steel production at Crewe.

In July 1866 Webb resigned from the LNWR and moved to the Bolton Iron and Steel Co. as the manager. It has been suggested that this move was arranged by the LNWR management to enable him to gain experience of steel making.

Ramsbottom gave 12 months notice of his resignation in September 1870. Shortly afterwards the Works Manager, Thomas Stubbs, died aged 34. Stubbs may have been Ramsbottom's intended successor. The Chairman of the LNWR, Richard Moon, contacted Webb and invited him to return to Crewe. In October 1870 Moon was able to inform Webb that his appointment as Locomotive Superintendent had been approved. Webb's salary was set at £2,000 for the first year, and £3,000 for the second and subsequent years. Webb took up his position on 1 October 1871. Webb became Chief Mechanical Engineer when the post of Locomotive Superintendent was renamed. It appears that this happened soon after Webb took up his duties. At the same time he also became President of the Crewe Mechanics' Institute, where he had for some time taught engineering drawing during his first stay at Crewe. Webb remained as CME of the LNWR until 1 July 1903, having tendered his resignation in November 1902. His successor, George Whale, was appointed in April 1903. Whale took over Webb's position somewhat earlier than planned, as Webb became seriously ill in June.

Webb was responsible throughout his career for some highly successful standard locomotive classes, all built at Crewe in considerable numbers. Notable amongst these is the Precedent class of 2-4-0 (known as Jumbos), an 0-6-0 general purpose freight design, ("Coal Engine") and its 0-6-2 ("Coal Tank") variant, a celebrated 0-6-0 mixed traffic design ("Cauliflowers"), and an 0-8-0 freight locomotive with two compound variants and a simple expansion version produced in parallel, The last-mentioned was continuously developed and built down to LMS days, most earlier locomotives being rebuilt to conform.

There does however remain some controversy over Webb's own two distinct compound systems applied to a number of locomotive designs, which are reputed to have given considerable trouble in service. The Webb Experiment or Improved Precedent class were withdrawn by his successor George Whale soon after he succeeded Webb in 1903.^{[citation needed]}

An obituary in The Engineer (8 June 1906) criticised his express compound design, which used un-coupled high and low pressure cylinders, a design promoted by Webb alone. The article caused open debate in the pages of the journal, mostly based on the perceived flaw of not utilising coupling rods. In the 20 June edition the editor of the journal continued the attack on the deceased engineer, stating: