Does anyone know????

[Anonymous]

Tried this question on the trains forum,but no onr knew the answer. kind of understand how the 2 cylinder american steam engine principles works.how did the Brits manage as much as 4 cylinders on some of their steam engines?How are those xtra cylinders hooked up to the side rods????? thanks Easter

[egmurphy]

See if any of these sources answer your question. These are all articles on "compound steam locos" with multiple cylinders.

http://en.wikipedia.org/wiki/Compound_locomotive

http://www.sdrm.org/faqs/boilers/page20.html

(see illustrations included in second article).


Regards

Ed

[Anonymous]

HEY cool. thanks egmurphy

[malcolmyoung]

Most British 4 cylinder locomotives had divided drive, that is the inside cylinders drove the leading coupled axle which was a two throw crank axle while the outside cylinders drove the second coupled axle via the normal crank pins. As the inside cylinders were 180 degrees out of phase with their adjacent outside cylinders, the valves of the inside cylinders were driven by a horizontal rocking lever from the outside cylinder valve rod (usually from the rear of the valve rod to avoid upsetting the timing of the inside cylinder valve due to expansion of the outside cylinder valve rod due to the heat of the steam). Thus, although they had four cylinders, they only had two sets of valve gear, usually Walschaets. The Great Western Railway four cylinder locomotives had two sets of Washaets valve gear between the frames plus the rocking levers to operate the outside cylinder valves.
There were a lot of three cylinder locomotives in Britain especially on the former London & North Eastern Railway, the most famous of which were designed by Sir Nigel Gresley. On these locomotives the three cylinders all drove the centre coupled axle which was a single throw crank axle and the valves were driven by Walschaets valve gear for the outside cylinders and the inside cylinder valve was driven by Gresley's derived motion. This was also used in the U.S.A. under a licencing agreement by Alco, most famously on the Union Pacific 4-12-2s amongst others. The Gresley motion was not without it's faults, however, and many three cylinder locomotive were fitted with three sets of Walschaets valve gear. The fastest steam locomotive in the world was a Gresley class A4 streamlined pacific No. 4468 "Mallard" which on the 3rd of July 1938 reached a speed of 126 M.P.H. This speed record has never been broken.