John D. Tilney was Cape Government Railways (Eastern System) Locomotive Superintendent (1874-1904).
Tilney carried out several experiments on some of the CGR 4th Class 4-6-0TT locomotives of 1880. One of his modifications was an extended smokebox to make room for a very efficient spark arrester, constructed of wire mesh. Another involved modifying the boiler and frame to accommodate oscillating firebars and a larger firebox to overcome the problems associated with the low-grade local coal from the Cyphergat collieries. Mechanical firegrate shaking was accomplished by means of a collar on the leading coupled axle which could be engaged by a roller with eccentrically mounted connecting rods to the oscillating firebars.[1][2][3]
- ^ Holland, D.F. (1971). Steam Locomotives of the South African Railways. Vol. 1: 1859–1910 (1st ed.). Newton Abbott, England: David & Charles. pp. 32–34. ISBN 978-0-7153-5382-0.
- ^ Espitalier, T.J.; Day, W.A.J. (1943). The Locomotive in South Africa - A Brief History of Railway Development. Chapter II - The Cape Government Railways (Continued). South African Railways and Harbours Magazine, October 1943. pp. 731-734.
- ^ Coal Burning on Cape Railways, Mechanical Engineers 1890, Plates 33 and 34.