Great Western Railway No. 3440 City of Truro was a 4-4-0 express steam locomotive built at Swindon in 1903 as part of the City class.
The locomotive became famous after a May 1904 run on the Ocean Mails special from Plymouth toward London.
During the descent from Whiteball Summit, timekeeper Charles Rous-Marten recorded quarter-mile timings that he later interpreted as indicating a peak speed slightly above 100 mph.
Because no dynamometer car or continuously calibrated speed recorder documented the run, historians continue to debate whether City of Truro conclusively became the first steam locomotive to exceed 100 mph.
The claim is therefore different from Mallard’s 1938 record, which was measured by a dynamometer car and is formally recognized.
City of Truro continued in service after the famous run and underwent mechanical changes over its career.
The locomotive was withdrawn, preserved, and later returned to operation during multiple preservation periods.
Its survival makes it one of the most important tangible artifacts from the Edwardian express era.
The locomotive carried different numbers and details over time, including renumbering under later GWR schemes.
For TransitSatellite, the page should present the 100 mph claim as a historically important but disputed inference from timing data, not as an unquestioned measured record.