Gibson LMS 2P 4-4-0

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David Thorpe
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Gibson LMS 2P 4-4-0

Postby David Thorpe » Sat Feb 11, 2012 8:30 am

A long long time ago (20 or so years) I started building the Alan Gibson kit for the LMS 2P 4-4-0 & Fowler tender. I built the body and tender, but it was then put aside and I have now resuscitated it for completion. Unfortunately, the instructions are no longer there and nor are some chassis parts, including the driving wheels. So I thought I'd better get some driving wheels and on going to the Alan Gibson site I noted that they have a 26mm 20-spoke wheel for the Midland 2P class. Fine, I thought, until I read elsewhere that these locos in fact had 6'9" drivers (which don't appear in the Gibson range). I'm tempted to assume that as Gibson produced both kit and drivers that the two would be right for each other, but the small amount of evidence I've subsequently been able to gather appears to be somewhat conflicting and I would be very grateful for any clarification anyone can give as to the correct driving wheels for this loco.

It's also the first 4-4-0 I've tackled. The kit came with Gibson sprung hornblocks for the drivers, with the front bogie (incorporating elementary compensation) sprung on a centre pivot. I've never got on with the Gibson hornblocks, and would greatly appreciate any advice as to the best way of compensating/springing a 4-4-0 of this type. Alan Rice, in his book on chassis building, suggests a fixed rear driving axle, with a compensating beam between the front driver and a rubbing plate on the bogie although that would seem awkward to achieve if one is to retain the central pivot for the bogie.

DT

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Will L
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Re: Gibson LMS 2P 4-4-0

Postby Will L » Sat Feb 11, 2012 10:03 am

Can be CSBed see here. You have to read to he end to get the 4-4-0 relevance. Also at the end you will find a link to another, earlier, thread which does a blow by blow on an 4-4-2 which is a 4-4-0 in disguise.

Will

Philip Hall
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Re: Gibson LMS 2P 4-4-0

Postby Philip Hall » Sat Feb 11, 2012 7:23 pm

I'm a compensation fan, old fashioned compared to CSBs, and I've found that the best way for a 4-4-0 (or a 0-4-4) is to have twin beams on the driving axles, and a compensated bogie supported in a conventional way with a slot and central bogie pin. This allows all the wheels to go up and down and the bogie to take a share of the loco weight. You might need to allow for weight transfer from the tender. I first copied this from a Finney M7 and T9 (although the Finney arrangement is for a rigid bogie) and it works well. Certainly all the locos with this awkward arrangement on 'Southwark Bridge' are built in this way, I think, and seem to pull and ride very well.

Philip

DougN
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Re: Gibson LMS 2P 4-4-0

Postby DougN » Sat Feb 11, 2012 8:57 pm

DT, I too have never really got Gibson horn blocks to work.So what I have done is to solder a 5 thou plate to the front face like Exactoscale and use them in the same way.

Ie the 5 thou plate is about 1mm bigger than the bearing all round therefore it can not move along the axle in to the centre of the chassis. I have also deleted the wire runner inside the horn guide as it is no longer needed.

I hope that helps.
Doug
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essdee
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Re: Gibson LMS 2P 4-4-0

Postby essdee » Sat Feb 11, 2012 11:46 pm

Davey,

On wheel diameter, the earlier MR 2P had 7ft 0in drivers, the later LMS derivative 2P had 6ft 9ins - both these being nominal maxima, and in service you would expect to see up to about 1.5inch tyre wear (ie 3inch reduction in diameter) before re-tyring; so you could fit a MR loco with 6ft 9ins wheel and an LMS example with 6ft 6ins and argue that they were due for shopping?.....

I cannot just remember whether they both had same number of spokes, but can check out for you?

On suspension, my own SDJR 2P (a MR version using Comet chassis on Hornby body with drive swapped from left to right, valances modified etc) uses the double beam and compensated bogie as advocated by Philip, and runs steady as a rock, at least on 'Dewsbury'.

Best wishes

Steve

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David Thorpe
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Re: Gibson LMS 2P 4-4-0

Postby David Thorpe » Sun Feb 12, 2012 12:27 am

Philip Hall wrote:.......and a compensated bogie supported in a conventional way with a slot and central bogie pin

Thanks for your suggestion, Philip. I'm a bit off CSBs at the moment, largely due to the difficulty of accommodating a High Level gearbox between the fulcrum points, so your system appeals. I'm just not sure what you mean about the "slot and central bogie pin" as quoted above and would be very grateful if you could clarify - forgive my ignorance, but this is the first time i've tackled a loco with a bogie of any type.

essdee wrote:On wheel diameter, the earlier MR 2P had 7ft 0in drivers, the later LMS derivative 2P had 6ft 9ins - both these being nominal maxima, and in service you would expect to see up to about 1.5inch tyre wear (ie 3inch reduction in diameter) before re-tyring; so you could fit a MR loco with 6ft 9ins wheel and an LMS example with 6ft 6ins and argue that they were due for shopping?.....


I'm pretty sure that the kit came with 24mm wheels and indeed 6'6" 20-spoke wheels are currently advertised by the Alan Gibson Workshop as the appropriate wheels for this kit which seems a bit strange as they also do a 6'8" 20-spoke.

DT

Philip Hall
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Re: Gibson LMS 2P 4-4-0

Postby Philip Hall » Sun Feb 12, 2012 1:08 am

David,

There are two ways to this form of bogie mounting. The first has a transverse slot in the bogie bolster plate (usually the frame spacer above the bogie) and a pin rising out of the bogie which passes through the slot and is secured by a washer and a nut to stop it falling out. The other way is the reverse of this, with the slot in the bogie stretcher, and the pin pointing downwards is secured to the frame stretcher, passing down through the bogie with the nut and washer below. The slot is to allow the bogie some sideplay and I usually make it some 8mm wide. Side control springs can, if required, be contrived to offer some resistance to the sideways movement, as discussed above.

My article in MRJ 205 has some pictures which show the idea. In the case of the Hornby M7, a short length of polythene tube secures the bogie, just as good as a nut.

Philip
Last edited by Philip Hall on Sun Feb 12, 2012 1:11 pm, edited 1 time in total.

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grovenor-2685
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Re: Gibson LMS 2P 4-4-0

Postby grovenor-2685 » Sun Feb 12, 2012 10:37 am

I'm pretty sure that the kit came with 24mm wheels and indeed 6'6" 20-spoke wheels are currently advertised by the Alan Gibson Workshop as the appropriate wheels for this kit which seems a bit strange as they also do a 6'8" 20-spoke.

I think here you have to decide which of three factors matters most to you.
a. Diameter
b. Crank pin throw
c. Number of spokes

a. If you go for a 6'8" wheel as closest to 6'9" i.e. not to badly worn, then you have to compromise on one of the other 2.. The 20 spoke wheel has a 13" throw for 26" stroke outside cylinders, but there is a 22 spoke wheel with 11" stroke and pin in line.

b. If you want the 11" throw for an inside cylinder loco then you can have 20 spokes at 6'6" dia or 22 spokes at 6'8" dia.

c. If you want 20 spokes then its 6'6" with 11" throw or 6'8" with 13" throw.

Isn't it difficult to cover everything even with Gibson's huge range.

Regards
Keith
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Flymo748
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Re: Gibson LMS 2P 4-4-0

Postby Flymo748 » Sun Feb 12, 2012 11:32 am

grovenor-2685 wrote:
I'm pretty sure that the kit came with 24mm wheels and indeed 6'6" 20-spoke wheels are currently advertised by the Alan Gibson Workshop as the appropriate wheels for this kit which seems a bit strange as they also do a 6'8" 20-spoke.

I think here you have to decide which of three factors matters most to you.
a. Diameter
b. Crank pin throw
c. Number of spokes

I'd say that Keith's right on that...

And for what it's worth, that would be the order that I would prioritise "accuracy" in as well.

Getting the elements that make it work mechanically - fit within splashers, have the right slidebar stroke (I know, not an issue on inside cylinders) - is to me far more important. At the end of the day, it's difficult to count spokes when the locomotive is whizzing by at a scale 60 mph :-)

Flymo
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David Thorpe
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Re: Gibson LMS 2P 4-4-0

Postby David Thorpe » Sun Feb 12, 2012 12:15 pm

Flymo748 wrote:Getting the elements that make it work mechanically - fit within splashers, have the right slidebar stroke (I know, not an issue on inside cylinders).... - is to me far more important.

Yes, I agree (particularly regarding the fit within splashers). As a result, I'm just going to play safe and go with the wheels that Gibson recommend for what is after all their own kit, ie the 6'6" ones. These locos would have pretty near the end of their lives anyway at the time I'm modelling, so considerable wear would be quite appropriate!

DT

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Hardwicke
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Re: Gibson LMS 2P 4-4-0

Postby Hardwicke » Thu Feb 16, 2012 5:25 pm

Exactly which class of LMS 4-4-0 is it? There were many variations and until they became the 483 class the wheels remained the original size whatever boiler and cab was stuck on top. Or is it actually the LMS built 2P? Have you still got the box or some of the etching?
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David Thorpe
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Re: Gibson LMS 2P 4-4-0

Postby David Thorpe » Fri Feb 17, 2012 11:30 am

Hardwick wrote:Exactly which class of LMS 4-4-0 is it?

I have the box - all it says is "LMS 2p & Fowler tender 4-4-0". I'm afraid I don't haver any useful etchings. It's obviously a great pity that i no longer have the instructions as they would presumably have made it clear. For what it's worth, here's a picture of the body and tender as built:

lms2p.jpg
LMS 2P and Fowler tender
lms2p.jpg (118.69 KiB) Viewed 6309 times


Thanks!

DT

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grovenor-2685
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Re: Gibson LMS 2P 4-4-0

Postby grovenor-2685 » Fri Feb 17, 2012 3:11 pm

That's the LMS one and looks very nicely put together.
Regards
Keith
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Keith
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Rdunning
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Re: Gibson LMS 2P 4-4-0

Postby Rdunning » Sun Mar 04, 2012 2:29 pm

DT,

For my money the best configuration for 4-4-0's is the one described in Roger Lycett-Smith's article "An EM Earl" in MRJ 126 of 2001. This is compensated, fixed rear axle, beam between front driver axle and centre of bogie. The beam is pivoted as near as practicable to the front axle so as to transfer weight on to the drivers. The clever bit is that the beam is arranged to bear on the bogie bottom stretcher underneath the bogie axle centre line and the bogie pivot is under the rear bogie axle. Connection to the main chassis is via a non-swinging link which allows only vertical movement of the bogie pivot relative to the main chassis. Weight is transferred from the tender via the Mike Sharman "free bogie" system.

I have built four 4-4-0's using this design and also an 0-4-4T. They all run rock-steady and trackholding is exemplary. One of the 4-4-0's (with the loco driven from a motor in the tender facilitating plenty of weight in the firebox/boiler) has the ability to start a train of 13 bogies on the straight. In contrast I made a Finney T9 as designed with twin beams and bogie pivoted on the centre pin and found it sadly lacking in traction. It would not haul a 3-coach set without slipping and I have since rebuilt it to the Lycett-Smith layout. I tried transferring weight from the tender via the drawbar but found that it had the unwanted effect of tipping up the front of the engine. (This doesn't happen with a fixed rear axle).

The upperworks look very neat, I hope your eventual choice of chassis works for you as well as they look.

Richard.

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David Thorpe
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Re: Gibson LMS 2P 4-4-0

Postby David Thorpe » Sun Mar 04, 2012 4:29 pm

Thanks very much for this,Richard - I am rummaging for MRJ 126 almost as I type....

Thanks also to you and Keith for your kind comments about my efforts with the kit so far. In fact, I put that lot together about 20 years ago, following which I gave up practocal railway modelling for a prolonged spell for a variety of reasons. I'm still trying to get these old skills back again!

DT

P.S. Have now located MRJ 126 - article looks very useful indeed!


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