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OO gauge GWR Mogul and Prairie


Paul.Uni
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1 hour ago, tomparryharry said:

Putting a class 3 loco on a class 6-7 load will end in tears. 

 

How about a class 2 on six coaches, and on the mainline ?

 

46443.

(not my image/flickr url)

 

didnt Jintys and Panniers take ecs’s off Euston, Paddington etc from long heavy trains ?

 

They can do it, it just might be a bit pedestrian.

 

Ages ago, I was told mainline railtours were planned in taking the power classification, doubling it and +1.. so a 2MT could do 5.. but clearly thats not an absolute formula. I did 45305 northbound on the S&C with 13 in a snow storm…but it did it, and back over shap and without a banker, but it did delay a few pendolinos.

Edited by adb968008
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If anyone thinks model Loco manufacturers put thought into designing and producing a Loco which will or only will match its prototype rating is sorely deluded……they make a chassis, it pulls half a dozen coaches, it’s fine, that’ll work, whether it’s a 0-6-0 Pannier or a Deltic is irrelevant to them, I have an old Thomas the Tank which will pull seven or eight coaches with ease and a Flying Scotsman that struggles with that same load.

 

Nah….sorry….to much faith in the Blue, Dark Blue and Red boxes.

 

:D

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40 minutes ago, JST said:

This must be a QC issue. There is a problem for manufactures here in a much as if a high profile reviewer gets sent a duffer they will call it out.

 

I think the problem is that we haven't really got used to the idea that there isn't QC and a number of returns are planned for. Hearing that there was a problem with the initial review model (even if then sorted) shouldn't really put us off these days but I hold my hands up that I would be wary.

 

We need to be clear that there is a difference between design issues, which by default will affect all of the models and one off problems (a duffer). The manufacturers approach to the latter is that they are happy to replace items and plan for a certain number of returns. So reviewing something that clearly has a problem is arguably misleading/unhelpful - it would be better to return it as advised and then comment in the review on how well the problem was resolved. If there is a repeat then absolutely that's worth flagging as may indicate a more widespread issue.

 

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19 minutes ago, boxbrownie said:

If anyone thinks model Loco manufacturers put thought into designing and producing a Loco which will or only will match its prototype rating is sorely deluded……they make a chassis, it pulls half a dozen coaches, it’s fine, that’ll work, whether it’s a 0-6-0 Pannier or a Deltic is irrelevant to them, I have an old Thomas the Tank which will pull seven or eight coaches with ease and a Flying Scotsman that struggles with that same load.

 

Nah….sorry….to much faith in the Blue, Dark Blue and Red boxes.

 

:D

I found Hornbys Peckett out performs its Duchess on my layout.

 

My Heljan DPU will out pull just about anything, its basically a brick on wheels with a motor even JCB would consider using.

 

For haulage you need two components.. weight and traction tyres, the latter brings out pitchforks in the UK, much to the amusement of the rest of the world who look at our poorly performing models and laugh at those complaining about it, whilst berating the globally accepted solution, but have no alternative to proffer.

 

Edited by adb968008
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5 minutes ago, adb968008 said:

 

How about a class 2 on six coaches, and on the mainline ?

 

46443.

(not my image/flickr url)

 

didnt Jintys and Panniers take ecs’s off Euston, Paddington etc from long heavy trains ?

 

Exactly right. Panniers did indeed do ECS work, with the humble 08 almost down to the present day. I think I'm right in saying that the Cambrian Coast route is not entirely 'flat' but is a lot less forgiving than Talerddig, as per your example. 

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7 minutes ago, tomparryharry said:

Exactly right. Panniers did indeed do ECS work, with the humble 08 almost down to the present day. I think I'm right in saying that the Cambrian Coast route is not entirely 'flat' but is a lot less forgiving than Talerddig, as per your example. 


I has a memorable moment of being rescued on the mainline at Taunton by a class 08 once… At least 12 loaded coaches, it dragged us all the way to Bishops Lydeard, where 53808 took over as the. BR 47/8 ran out of fuel… not a window wasnt occupied for that part of the journey. :D

Edited by adb968008
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8 minutes ago, adb968008 said:

I found Hornbys Peckett out performs its Duchess on my layout.

 

My Heljan DPU will out pull just about anything, its basically a brick on wheels with a motor even JCB would consider using.

 

You gotta love Heljan for traction power, I think their chassis are made from depleted Uranium :lol:

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54 minutes ago, tomparryharry said:

Exactly right. Panniers did indeed do ECS work, with the humble 08 almost down to the present day. I think I'm right in saying that the Cambrian Coast route is not entirely 'flat' but is a lot less forgiving than Talerddig, as per your example. 

 

The climb out of going south out of Fairbourne/Friog is 1 in 55

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59 minutes ago, adb968008 said:

I found Hornbys Peckett out performs its Duchess on my layout.

 

My Heljan DPU will out pull just about anything, its basically a brick on wheels with a motor even JCB would consider using.

 

For haulage you need two components.. weight and traction tyres, the latter brings out pitchforks in the UK, much to the amusement of the rest of the world who look at our poorly performing models and laugh at those complaining about it, whilst berating the globally accepted solution, but have no alternative to proffer.

 


Now wait for the usual derisory howls. Having a considerable number of European HO models,I fully endorse that statement. They also have considerable mass/ weight in addition. However,this side of the channel………etc……..perceived wisdom dictates otherwise 

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16 hours ago, Miss Prism said:

There is no excuse for bits of plastic to be higher than the metal rail surface in any item of point and crossing work.

 

Unfit for purpose, plain and simple.

 

 

They've only been like that 40+ years though...

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On 05/12/2021 at 18:48, rembrow said:

<snip>

Having seperated the pony truck by the two screws, I've removed the springs and reduced their length by a quarter. This relieves the pressure on the axle.

<snip>

 

On 06/12/2021 at 12:00, adb968008 said:

Agree it sounds like its over compensated on the springs, trimming the spring may work too.

 

Quote

A softening of the springs is still a good option, they feel quite strong but not strong enough to lift the loco.

 

 

Just an observation here on the physics of springs. By shortening the springs you do two things: 1) increase the spring rate and make them stiffer. 2) when installed in the same way, reduce the preload on the springs. By doing this, you can reduce the force need to start moving the spring, but then require more force to move it the same distance as before. Ideally, the amount of preload needs to be balanced with the mass of what is being suspended (e.g. in this case the unsprung mass of the loco)

 

Examples.

1. A spring with a rate of 1N/mm and no preload will compress 1mm for every Newton applied (1N to move the first 1mm, then 1N for every 1mm thereafter). 1N,1mm; 2N,2mm; 3N,3mm; 4N,4mm.

 

2. A spring with a rate of 1N/mm and 2mm of preload applied will require 3N to move the 1st mm, then 1N for every 1mm thereafter.

3N,1mm; 4N,2mm; 5N,3mm; 6N,4mm.

 

3. A spring with a rate of 2N/mm and 1mm of preload applied will require 4N to move the 1st mm, then 2N for every 1mm thereafter.

4N,1mm; 6N,2mm; 8N,3mm; 10N,4mm.

 

It's all a big balancing act to manage the two properties and you can get yourself in a pickle if not done right (30+ years of tuning motorcycle forks has taught me this!). If the pony wheels are not moving with the available mass of the loco, you can either add mass, fit softer springs (same length, more coils or thinner wire) or, reduce the preload as you have done here.

Edited by 57xx
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2 hours ago, 57xx said:

 

 

 

 

Just an observation here on the physics of springs. By shortening the springs you do two things: 1) increase the spring rate and make them stiffer. 2) when installed in the same way, reduce the preload on the springs. By doing this, you can reduce the force need to start moving the spring, but then require more force to move it the same distance as before. Ideally, the amount of preload needs to be balanced with the mass of what is being suspended (e.g. in this case the unsprung mass of the loco)

 

Examples.

1. A spring with a rate of 1N/mm and no preload will compress 1mm for every Newton applied (1N to move the first 1mm, then 1N for every 1mm thereafter). 1N,1mm; 2N,2mm; 3N,3mm; 4N,4mm.

 

2. A spring with a rate of 1N/mm and 2mm of preload applied will require 3N to move the 1st mm, then 1N for every 1mm thereafter.

3N,1mm; 4N,2mm; 5N,3mm; 6N,4mm.

 

3. A spring with a rate of 2N/mm and 1mm of preload applied will require 4N to move the 1st mm, then 2N for every 1mm thereafter.

4N,1mm; 6N,2mm; 8N,3mm; 10N,4mm.

 

It's all a big balancing act to manage the two properties and you can get yourself in a pickle if not done right (30+ years of tuning motorcycle forks has taught me this!). If the pony wheels are not moving with the available mass of the loco, you can either add mass, fit softer springs (same length, more coils or thinner wire) or, reduce the preload as you have done here.

I wonder what the answer from Dapol would be with a question of “what is the rate of the springs on the new Prairie and the preload if any please?”

 

hmmm ;)

 

Heaven help us when they start fitting dampers and we need to change the rebound and compression rates :lol:

Edited by boxbrownie
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45 minutes ago, boxbrownie said:

I wonder what the answer from Dapol would be with a question of “what is the rate of the springs on the new Prairie and the preload if any please?”

 

hmmm ;)

 

Heaven help us when they start fitting dampers and we need to change the rebound and compression rates :lol:

When I was a teenager I bought a model aero Diesel engine . I wrote to ask the manufacturer, What is the temperature and pressure in the cylinder ? They replied “Very hot and very high”.

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1 hour ago, boxbrownie said:

I wonder what the answer from Dapol would be with a question of “what is the rate of the springs on the new Prairie and the preload if any please?”

 

hmmm ;)

 

Heaven help us when they start fitting dampers and we need to change the rebound and compression rates :lol:

 

Damping is a doddle :P Not had a modern enough bike to have to deal with high and low speed damping circuits though.

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9 hours ago, Jenny Emily said:

The example I reviewed ran just fine over all my pointwork. 
 

 

But would it be fair to say that yours was directly from Dapol as a review sample so would have been pretty well run-in and/or sorted before you got it?

 

 

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Thanks for the review Jenny.

A few observations :-

1 Your point about the running plate and body fit was well made but if you view earlier posts in this thread you will see this is not always the case.

2 The gap between the whistle pipes and cab is there because the cab roof does come off.

3 It is not good practice to use pliers on the “daughter board”. The tool for removing the smoke box door is also designed for removing this board.

4 I love my Dapol Mogul dearly but one failing is the firebox flicker which is virtually non existent. In your review I couldn’t see if the Prairie was any better.

Hopefully my sound fitted version should arrive soon!

Regards
John

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On 07/12/2021 at 10:30, adb968008 said:

 

How about a class 2 on six coaches, and on the mainline ?

 

46443.

(not my image/flickr url)

 

didnt Jintys and Panniers take ecs’s off Euston, Paddington etc from long heavy trains ?

 

They can do it, it just might be a bit pedestrian.

 

Ages ago, I was told mainline railtours were planned in taking the power classification, doubling it and +1.. so a 2MT could do 5.. but clearly thats not an absolute formula. I did 45305 northbound on the S&C with 13 in a snow storm…but it did it, and back over shap and without a banker, but it did delay a few pendolinos.

Contemporary mainline steam workings are an irrelevance when it comes to looking for historical loading information.  The reason for this is that unlike the 'real railway' steam operation is totally different from what happened in the everyday world.  first of all the engines are almost always in tip-top mechanical condition using good quality coal (yes, I know of occasional exceptions).  And the loads they haul are far more a consequence of commercial pressure to make sure the trip is profitable than it is to take cognisance of what the Loads Book used to say and the times against which Loads Book loads were calculated.

 

When i was planning mainline steam working I always used the old Load Tables and timings and every time commercial pressure resulted in heavier loads trains tended to  lose time against the old booked times unless everything was absolutely perfect,  But if things were perfect you would usually get a punctual run even with a larger load.

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On looking at the various YT videos, it looks as though the stalling is on Insulfrog points, I am wondering if live frogs would be OK, and due to last years lockdown purchases, out of my 22 points only 3 are Insulfrog the rest Electrofrog, and only one would need to be replaced.  Still unsure about a purchase without some evidence a non DCC won't stall over live frogs.

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3 hours ago, confused said:

On looking at the various YT videos, it looks as though the stalling is on Insulfrog points, I am wondering if live frogs would be OK, and due to last years lockdown purchases, out of my 22 points only 3 are Insulfrog the rest Electrofrog, and only one would need to be replaced.  Still unsure about a purchase without some evidence a non DCC won't stall over live frogs.

Live frogs will reduce the locations where stalling is likely, and my Prairies ran fine over my live frog turnouts, but any small length of non-conducting track would show the basic problem, which is that on some of these locos only one set of wheels might at times be picking up electricity/signal from the track because of the two problems:

 

1. The rear pony ("radial truck"?) applies some upwards force to the rear driving axle because of the springs within it and it doesn't allow the pony axle to travel upwards very far anyway so there's a tendency for it to lift the rear driving axle off the track.

2. The middle sprung axle doesn't have enough freedom to move below the outer driving axles - so if either end is lifted the middle axle can't drop down to make contact with the track and so can't compensate for problem 1.

 

See @outatime's modifications above to solve these problems.

 

Edited by Harlequin
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6 hours ago, 97xx said:

But would it be fair to say that yours was directly from Dapol as a review sample so would have been pretty well run-in and/or sorted before you got it?

 

 

You would have to ask Dapol that question. I just review them as I find them. 

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28 minutes ago, Jenny Emily said:

You would have to ask Dapol that question. I just review them as I find them. 

I presume 97xx meant yours was a review Model sent direct from Dapol rather than a shop bought model by yourself?

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4 hours ago, Jenny Emily said:

You would have to ask Dapol that question. I just review them as I find them. 


There seems to be some anecdotal evidence that DCC versions perform better through pointwork than analogue ones.I cannot imagine that the one you tested could have been specially fettled,by Dapol. 

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