Valve gear simulators

Hello, I am building a 5 inch gauge Crampton, Le Continent. I am using the drawings produced in France by STEAM. I don't think this company exists anymore. I have scaled down from 71/4 gauge. I have been trying to simulate the valve gear on Charlie Dockstader's program but find I can't get the rocker link to work. It's an unusual link in that it is pivoted at one end rather than in the middle. I want to simulate the valve gear because I have never heard of anyone else building this model in 5 inch gauge and it could save a lot of work and tearing of hair out! Could anyone who has experience of this program please help?

Hi John,

I havent used Dockstader but use the Hall Simulator a lot at various times, and have had a go with the Alan Wallace Simulator.

There are 2 issues.

1. The Rocker arm (this is very easy with the Bill Hall simulator

2. The top or bottom suspended links.

The top or bottom suspended arrangement is very sensitive to weighshaft arm dimensions and lifting link lengths, and positioning of the weighshaft itself.

If you would like to PM me your email address we can perhaps discuss further.

Cheers,

Julian

Thank you for the reply. I've tried using the Hall Simulator as well but it just came up with Domain Error. I've been thinking about this and wonder if the problem is that I am treating it as a slide valve on top arrangement whereas the valve face is inclined so as the bring the valve rod in line with the axle centre line. I don't see anything on the simulators to allow for this.

Hello John,

The Crampton has been built a number of times in 5"/127mm gauge. Here is a video of one. You may be able to track builders/info etc., through cav-escarbille if you are unaware of it.

As you probably know the plans from STEAM are a representation, rather than a scale model. My attempts to get scale plans from The French National Rail Museum ended in failure, even though scale plans are available elsewhere! (I am building in 7 1/4 in gauge.)

Can't help with your question as regards valve simulators tho' I'm afraid.

Regards, & bonne chance,

Phil

Hello Phil,

Thank you for your feedback. I wasn't aware that the STEAM drawings aren't to scale but It looks great and I'm not bothered about having an exact scale model. I am sure that anyone who sees it here in Ireland will never have seen the real one so how will they know it's not exactly right? I tried to get some photographs of the original out of Musee du Train but never even got a reply. I don't speak French so that would not have helped. Are you building this engine also? Do you know anyone who has photographs of the original and who would be willing to send me the images?

Kind regards,

John

Hello John,

I have some photos of details of No.80 - these show features that interest me, and may not be of use to you, but I am happy to send you copies if you send me a personal message with your email address. Warning: It will take me a while to sort the pics out.

There are 'overall' pictures around on-line of course; notice all those lovely bolts holding the thing together and missing from the STEAM drawings, and the differing bolt patterns of the locomotive axle horns. There is also a contemporary 7 1/4 inch gauge model of a similar, albeit slightly earlier French Crampton exhibited in the London Science Museum.

This looks to be a nicely detailed 5 inch gauge version which is turned over and around to show all the detail - much of which, as noted above, is missing from the STEAM plans. The dimensions on the STEAM plans are also not to scale, I suspect in large part to allow the use of standard (French) sizes and sections of materials. However the casual viewer will not notice these things.

As regards exact representation of a particular locomotive then of course the STEAM drawings are close(ish) to No.80, Le Continent. However No. 80 was one of a class of 27 Locomotives (Numbered 79-90 & 174-188, all named), so, if you are so minded....... choose another number & name combination and challenge someone to tell you that you are 'wrong'. Pics of some, perhaps all, of them exist, and there are minor variations between individual machines, and of course changes throughout their working lives with weatherboard cabs, various fittings, etc., being added.

I am building one in 7 1/4 inch gauge , 'as and when', so progress is s l o w. Machining the cylinders needed some careful and bizarre set-ups to achieve all those strange angles! And I would point out that the clearance between the cross-heads and the spring supports for the central axle are tight (1mm clearance in my case) - you may have spotted this, but if not...... and of course the water pumps need very careful lining up with the cylinders.

Otherwise a straightforward machine; ummmmm, I think.

Regards,

Phil.