Talk:Holcroft valve gear

Unreliable source?
< To achieve this, Holcroft introduced a method of driving a middle cylinder from the right-hand set of "outside" Walschaerts valve gear, eliminating the use of a separate set of valve gear between the frames.[2] The middle cylinder was driven from the combination lever assembly that controlled the fore and aft movement of the valve spindle on the right-hand "outside" cylinder. >

It is very probable, to say the least, that the following propositions are true:

P1 The middle valve was driven from both outside cylinders.

P2 The middle valve was driven from the point on each combination lever that drove its valve. In effect, therefore, the middle valve was driven from the 'cold' end of the outside valves.

(Gresley picked up the cold, rather than hot, ends on the D49/1 class).

86.183.83.192 (talk) 22:42, 16 September 2012 (UTC)

Abandonment of Holcroft Gear
It would be good to have information on why the SR stopped using Holcroft conjugation. Holcroft is silent on the subject and I can't find anything else on line. 212.159.44.170 (talk) 17:05, 2 November 2014 (UTC)

Four Cylinder Version
It is well know in modelling circles that Holcroft and LBSC were close friends and Holcroft designed a four-cylinder version of his gear for one of the latter's models. I have dug out and read the original LBSC article and summarised it for the entry. It's an unusual example of a locomotive designer innovating in both full size and miniature!Stub Mandrel (talk) 22:46, 17 February 2018 (UTC)