| GWR 3511 to 3520 | |
| Powertype: | Steam |
| Designer: | William Dean |
| Builder: | GWR Swindon |
| Ordernumber: | 64 (part) |
| Serialnumber: | 1016–1025 |
| Builddate: | 1885 |
| Totalproduction: | 10 |
| Uicclass: | 1B |
| Leadingdiameter: | 3feet |
| Driverdiameter: | 5feet |
| Wheelbase: | 17feet |
| Fueltype: | Coal |
| Tubearea: | 1106.57square feet |
| Fireboxarea: | 103.29square feet |
| Totalsurface: | 1209.86square feet |
| Superheatertype: | None |
| Cylindercount: | Two, inside |
| Cylindersize: | 17x |
| Valvegear: | Stephenson |
| Trainheating: | Steam |
| Operator: | GWR |
The GWR 3511 class were standard gauge locomotives designed by William Dean for the Great Western Railway and built in 1885.
They comprised the last ten of the twenty locomotives of Lot 64. The first ten locomotives of this Lot were built to the broad gauge as the 3501 class.
Originally built with condensing apparatus they were used on work through the Severn Tunnel until the ventilation was improved.
The condensing apparatus was soon removed and in 1894/5 they were all rebuilt as tender locomotives of the 3201 class as were the 3501 class.
. Harold Holcroft . An Outline of Great Western Locomotive Practice 1837-1947 . 1957 . Ian Allan Ltd . Shepperton, Surrey, UK . 0-7110-0228-2.