Fitting roundhouse valve gear?

[Joe]

Hi all,
Just thought id ask in case anyone has tried it; im looking to start to build a new steamer for my line but i quite fancy the challenge of making it unique and not just another katie/lady anne (as much as i do admire those locos). I haven't got an array of machines and tools etc but ive had an idea of making my own frames (with roundhouse frame spacers between) and attaching roundhouse valve gear ,cylinders and wheels to that. That way i can make a loco how i want with trailing wheels and extended front end etc. The only issue i can think of is how easily the valve gear goes together and whether roundhouse valve gear can be extended if i decided to go for a longer wheel base engine etc.
any advice on the matter would be much appreciated.
Cheers
Joe

[LNR]

Hi Joe, depends if you need to actually extend the valve gear. If you do as I did for my 2-6-2 Bagnall inspired loco, and extend the eccentric and connecting rods only, you're not changing valve events to any degree.



You may also be able to move the connecting rod to the centre axle in the case of a six coupled loco, just remember shortening the rods equals more angularity (more load on glands in the case of Roundhouse cylinders). I've never been fond of the way Roundhouse bend their rods with double cranks in them to line things up, and prefer to make them straight as real rods, with less noticeable cranks right at the ends.
Grant.

[IanC]

As LNR says, the rods should be straight. No doubt someone will prove me wrong but in view of the forces applied I've never seen bent connecting rods on any locomotives.

Ian