Built-in 1878 by Hughes’ Loco & Tramway Eng. Works Ltd of Loughborough this 0-4-2ST (originally 0-4-0ST) worked on the nearby Corris Railway until the closure of that line in 1948. In 1951 it was purchased by the Talyllyn Railway (along with the other surviving Corris loco which became ‘Edward Thomas’) and was named after the line’s late owner, Sir Henry Haydn Jones. The precarious state of the track led to its being little used for the first few years, and firebox problems caused its withdrawal in 1957. It re-entered service in 1968.
In 2018 Sir Haydn returned from a major overhaul at the Vale of Rheidol Railway in Aberystwyth, and is now proudly hauling trains up the valley in our “TR Standard Green” livery.
CURRENT STATUS: Operational
| Maker | Hughes’ Loco & Tramway Eng. Works Ltd. |
| Year | 1878 |
| Works number | 323 |
| Type | 0-4-2ST |
| Driving wheel diameter | 2′ 5 1/2″ |
| Trailing wheel diameter | 11″ |
| Coupled wheelbase | 4′ 0″ |
| Total wheelbase | 8′ 3 1/2″ |
| Cylinder size (bore/stroke) | 7 1/4 x 12″ |
| Heating surface | 153 sq. ft. |
| Working pressure | 160 psi |
| Tractive effort @ 85% BP | 2900 lbs |
| Weight | 9 1/4 tons |
| Length over buffers | 16′ 6 1/2″ |
