Hackworth valve gear

It is a radial gear, with an actuating lever driven from the crank.

The other end of the actuating lever is attached to a die block which slides in a slotted link.

Forward, reverse and cut-off adjustments are made by moving the link away from the vertical.

The valve rod is pivoted to a point on the actuating lever.

[2] Hackworth valve gear was a precursor to Klug's valve gear, but it differs from the latter in that the eccentric rod's suspension point moves to-and-fro in a straight line by means of a die block sliding in a slotted guide.

Hackworth valve gear on steam locomotive ' Lydia ' at the Perrygrove Railway .
Hackworth valve gear on Apedale Valley Light Railway locomotive ' Stanhope '
Hackworth valve gear on Tal-y-Llyn Railway locomotive ' Edward Thomas '