Crime or misdemeanour

Holcroft was pretty good, too: the mogul that he and Maunsell did between them was probably the first really "modern" steam locomotive in .uk

Some people rate Robinson, too, and Earle Marsh certainly played a big role in the design of the GNR atlantics.

Reply to
Andrew Robert Breen
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Well, it couldn't be a OO model, could it? 4mm/', maybe, but 4mm/' and

16.5mm gauge would be noticably inaccurate for one of those things ;0

OTOH, if it was modelled in 4mm/' and 28mm gauge (or 24.5mm gauge, if you insist on OO-broad ;) it probably would do OK on those curves. Railways in the 1840s and 50s tolerated much tighter curves than later - the precise reason for those flangeless drivers on Patentees of all sorts (and the B&E tanks) was to get 'em around the tight bends which were common in stations and yards.

It's one reason why I'm surprised that the pionnering period isn't modelled more - it would be ideal for minimum-space modelling.

Reply to
Andrew Robert Breen

OK, for the purpose of discussion, lets say OO broad, not that it really matters when discussing 2nd radius curves. I'd forgotten about the 7ft bit ;-) Probably even less likely to get around 2nd radius ;-)

Kevin Martin

Reply to
Kevin Martin

I'd have a deal of confidence in the ability of engines of that era to cope with surprisingly square corners: an inspection of station and yard plans from the time tends to show up some remarkably tight bends (which, of course, was why most engines with more than four wheels had a pair without flanges...).

Reply to
Andrew Robert Breen

Quite possibly

But this particular class had *all* drivers flangeless.

Kevin Martin

Reply to
Kevin Martin

As did any single-driver engine built to Stephenson's patent (the Patentee type), which //specified// flangeless drivers. Most[1] single-driver locomotives of that time (Burys apart, obviously..) had all their driving wheels flangeless.

It was the combination of bogies and flangeless drivers which made the Pearson engines remarkable for their day[2] - the inspiration was an

8-wheel carriage, and they were intended to have similar dynamics. [1] One company - I forget which for the moment - got around the Stephenson patent by using thin flanges on the driving wheels, but most used flangeless wheels and got around the patent in other ways. [2] Well, that and using an iron strut in /compression/ to carry the suspension loads for the driving axle..
Reply to
Andrew Robert Breen

Don't forget the bogies on the Pearson tanks had no side movement, just a simple centre pivot, so it was like a carriage. Also the Gooch

4-4-0s and 4-2-2s didn't have bogies but had the carrying wheels attached rigidly, like uncoupled 0-8-0s.
Reply to
Christopher A.Lee

So did a lot of other engines of the time. Like the Patentees and their Gooch derivatives.

Remember that bogies of that era had simple ball and socket type pivots with no side movement. And the 4-2-4 tanks of that era were no different. So its drivers had to be flangeless.

Reply to
Christopher A.Lee

Gooch's 4-4-0 tanks had a primitive sort of bogie, though. No side-play, of course.

Anyway, how about an 8-coupled (well, 4+4 coupled..) locomotive with all driving wheels flangeless..

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NOt sure about the scale, and the cost is undoubtedly "if you have to ask...", but don't these just give ideas....

Reply to
Andrew Robert Breen

That's why I said 4-4-0 not 4-4-0T. The tanks' bogies had a simple ball and socket that gave no side movement.

Of course those were plateways.

Reply to
Christopher A.Lee

Sorry, I wasn't trying to make an absolute rule for the entire world. The 'problem' is with side movement of the extremities of the loco on (sharp) curves. I aim at getting the front, center and rear of the loco sharing the offset. This occurs when the fixed axle wheelbase is circa

0.7 of the total length. (much like a coaches bogie pivot placement) That effectively puts the ideal fixed axle positions near or beyond the actual axles of an 0-8-0 and on a 2-8-0 between the truck and first coupled axle and at/beyond the rear driven axle. The forward 'fixed point' on a 2-8-0 can be effectively moved forward by introducing side springing on the truck axle and the forward driving axle. For a 2-8-0 I like to bring the forward fixed point back a little from the theoretical. That increases the front beam offset and decreases the rear offset. The rear offset looks best when it varies the least compared to the tender offset (on curves) Extending the effective fixed wheelbase of course increases the driver offsets which affects the valve gear width. It's something of a juggling act.

Certainly you can do it that way, but the negative is in greatly increased end offsets. My HO 2-12-0s are of course somewhat smaller locos than the OO scale 9F, much the same size as the German BR44s. :-)

Greg.P.

Reply to
Greg Procter

No problem if I build it for 16.5mm gauge. ;-);-);-);-);-);-);^),

Greg.P. NZ

Reply to
Greg Procter

The 9F didn't have flanges on the center drivers! (but you knew that!)

Greg.Pedantic. NZ

Reply to
Greg Procter

No problem - fixed pivots on both bogies moved inwards a little until the drivers stay on the railheads. Widen the driver tyres to about 4.5mm and center the wheels to match the rail head centers.

Greg.P.

Reply to
Greg Procter

Its an OO kit. Probably nothing wrong with the design but its only my second attempt at assembling a chassis. I didnt use the recommended motor/gears cos didnt know what they were till I got the kit.

When have been playing as long as certain experts then maybe will do better - doubt it though as have poor connections between hands and brain. Also in too much of a hurry.

Cheers, Simon

Reply to
simon

You are cruel - would have liked to have been there though.

But his writing is excellent and have learnt lots of useful stuff from his books.

Cheers, Simon

Reply to
simon

She's lovely, but wondered if you had any personal contact and could get me an introduction.

I bought a Skaledale Tardis - can claim the trainset is in a different era just by moving it around. Is there an 4mm model of Ms Piper ?

Cheers, Simon

ps wont ever ever ever forgive your remark about Crewe.

Reply to
simon

Chuffing eck - that shouold be called a 'paddle' tank !

Cheers, Simon

Reply to
simon

"simon" wrote

VBG - the reality was that his layout was a wonderful example of his 'proscenium arch' philosophy, it was simple but beautifully detailed. The sad reality though was it didn't operate satisfactorily.

I've read dozens of modelling books over the years, but the one which stands out in my mind as a genuine learning tool was Guy Williams 'Locomotive Construction in 4mm scale'.

Beautifully written in a manner which really helped me as a fledgling modeller in the early 70s with many scratch building techniques - all of which worked! Even today it has relevance to anyone wanting to build models of steam locos. A true genius whose worked helped to create the marvel which is Pendon.

John.

Reply to
John Turner

I haven't but you can see her getting quite a bit of personal contact in a future ITV production. She allegedly took lessons from a real life dominatrix in how to wield a whip :o)

You read it wrong. I meant that any model is okay as long as the original originated from there.

(kim)

Reply to
kim

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