Chittaprat

Following the success of Puffing Billy and Wylam Dilly in 1813–14, William Hedley continued experimenting at Wylam Colliery. Chittaprat was a third Wylam engine of broadly similar two-cylinder grasshopper-beam pattern, built at the colliery's own workshops with engineman Jonathan Forster and blacksmith Timothy Hackworth. The valve gear, however, was not as carefully balanced as on its predecessors and the engine emitted a markedly uneven exhaust beat — onomatopoeically rendered "chitta-prat" — from which the locomotive took its name.

Chittaprat entered service at Wylam in 1815 but never matched the reliability of Puffing Billy or Wylam Dilly. The boiler is reported to have failed, and the engine was withdrawn after a short working life. The remains are believed to have been scrapped or cannibalised at the colliery; no parts survive.

Externally similar to Puffing Billy: a substantial cylindrical wrought-iron boiler with twin vertical cylinders set on either side of the boiler casing, driving the wheels through grasshopper beams and side rods. The engine's defining feature was audible rather than visual — the irregular exhaust beat that gave it its name.

• Chittaprat (1815)