The GWR 3501 Class were ten broad gauge 2-4-0 locomotives built by the Great Western Railway.They were built in 1885 as 2-4-0T tank locomotives, but five were rebuilt in 1890 as 2-4-0 tender locomotives for working express trains between Exeter and Plymouth. They comprised the first ten locomotives of Lot 64, the remainder of which comprised ten similar locomotive Nos. 3511 to 3520 built to the standard gauge.