Wright writes.....

[Chuffer Davies]

3 minutes ago, t-b-g said:

What has always baffled me, from a physics point of view, is that you can get a pair of tweezers and lift an individual wheel on a sprung mechanism really easily. If you try to lift an individual wheel on a rigid mechanism, you have to lift the whole loco up and it is much harder to do.

 

So the rigid one must grip the track better. Obvious innit!   

Tony,

What a super demonstration of how not understanding the physics can lead to false conclusions.  I know you’ve written this very much with your tongue firmly pushed into your cheek to see if I would bite, so I have.  
 

To explain: When you lift the one wheel on a sprung/compensated chassis the weight you lift is solely that carried by that wheel because the springs/compensation are doing precisely what they are supposed to do.  With a rigid chassis when you lift the equivalent wheel you are at the same time lifting all the wheels on that side off the locomotive so the combined weight previously carried on multiple wheels is now transferred to the tweezers hence there is more resistance.  
 

To quote you, ‘obvious innit’!

 

Frank

[MJI]

I have had the first of my 4-4-0s arrrive, got chassis issues.

 

Got a few choices

1) loose bogie as per rtr

2) hard pivot on bogie with rear sideplay

3) rigid on all 8 with sideplay on outer axles

4) 4B bogie both ends

5) 2 2 4 0 with pony

 

Current layout is 2 foot smallest on some points, However these MAY end up on a finer scale layout (either Peco Bullhead or a try at EM). SMALL layout.

[t-b-g]

7 minutes ago, Chuffer Davies said:

Tony,

What a super demonstration of how not understanding the physics can lead to false conclusions.  I know you’ve written this very much with your tongue firmly pushed into your cheek to see if I would bite, so I have.  
 

To explain: When you lift the one wheel on a sprung/compensated chassis the weight you lift is solely that carried by that wheel because the springs/compensation are doing precisely what they are supposed to do.  With a rigid chassis when you lift the equivalent wheel you are at the same time lifting all the wheels on that side off the locomotive so the combined weight previously carried on multiple wheels is now transferred to the tweezers hence there is more resistance.  
 

To quote you, ‘obvious innit’!

 

Frank

 

I know. It is the way my simple brain works sometimes.

 

Of course when you have a sprung bogie or trailing wheel some of the weight available for traction goes onto that rather than the drivers.

Edited July 30, 2020 by t-b-g
Spelling

[Chamby]

2 hours ago, LNER4479 said:

Roy delighted in telling me the tale on my one and only visit to Retford.

 

May I be the one to say that chassis compensation and side control of bogies are actually different things?

 

This loco is my only essay (to date) in bogie side control - it has a 'proper' lateral springing between the bogie frames, acting on the bogie pivot pin exactly as per the full-size thing. It rides like a Rolls-Royce and negotiates curves down to two foot radius with ease.

 

One interesting aspect, being a pacific, is whether to do anything similar for the rear pony truck? This one on this loco just flops around and I think it is quite noticeable when curving through pointwork how much the cab swings out in relation to the tender, particular when in reverse.

 

My take? Fun to do and satisfying when it all works - but I can fully understand when there is a time imperative for a professional builder then, unless the buyer is prepared to pay extra, then not really worth doing.

 

Logic says to me that if you reduce the extent to which the cab swings out compared to the tender, then you would cause a corresponding increase in the extent to which the front end swings out, because the body is rigid along its length.  That would perhaps be even more noticeable on a two foot radius curve!

[Chuffer Davies]

1 minute ago, t-b-g said:

 

I know. It is the way my simple brain works sometimes.

 

Of course when you have a sprung bogie or railing wheel some of the weight available for traction goes onto that rather than the drivers.

Now that I can agree with.  
 

In reality you only need light downward pressure to allow the side control to work as long  as the forces are acting below the centre line of the axle.  The greater the distance above the centre line the side  control acts on the bogie or pony truck the more down force is needed to stop the wheels from canting over and derailing.  
 

This is also why, if a loco is nose heavy typical of a 4-4-0,  I always mitigate this by hanging the tender on the draw bar which increases the weight on the driven axles, rather than increase the strength of the spring on the front bogie/pony truck which reduces the weight on the driven axles.

 

Frank

[Chuffer Davies]

18 minutes ago, Chamby said:

 

Logic says to me that if you reduce the extent to which the cab swings out compared to the tender, then you would cause a corresponding increase in the extent to which the front end swings out, because the body is rigid along its length.  That would perhaps be even more noticeable on a two foot radius curve!

Hi Phil,  you are correct but there is one other element you are missing.  Unless the locomotive is right on the edge of being able to negotiate the radius of  the curve then there will be some lateral twist to play with.  Without any side control on the trailing axle the cab will swing out as far as it is able to.  If the trailing axle has side control fitted then this will encourage the loco to straighten up as far as it is able through the curve.  It’s all very subtle and I can hear Sir snoring in the background, but sadose like me love this stuff.  
 

Frank

[Headstock]

18 minutes ago, Chuffer Davies said:

Hi Phil,  you are correct but there is one other element you are missing.  Unless the locomotive is right on the edge of being able to negotiate the radius of  the curve then there will be some lateral twist to play with.  Without any side control on the trailing axle the cab will swing out as far as it is able to.  If the trailing axle has side control fitted then this will encourage the loco to straighten up as far as it is able through the curve.  It’s all very subtle and I can hear Sir snoring in the background, but sadose like me love this stuff.  
 

Frank

 

Afternoon Frank,

 

not sad, thoughtful modeling.

[jamie92208]

Just be grateful that you're not modelling a Gibson 7mm 4-4-0's. 3 of us got a 483, a 3P 700 and a 990 between us. The bogie pivot in all cases was an 8BA bolt through a spacer and the bogie centre. No sideplay at all. We all solved thecproblem differently but needed to allow at least 1/8" movement each way for the bogie to allow the locos to negotiate 5'6" radius curves.  I pivoted my bogie from a frame spacer quite near to the front coupled axle then madecan arc shaped slot for a long 8BA bolt to slide in and coupled the bogie to it's pivot with a piece of square brass tube.  A spring round the long 8BA bolt was made to bear on the centre of the bogie but below the axles.  The gave a small element  of side control as well as keeping the bogie on the track.  It works well. I won't go on at length about all the other dimensonal innaccuracies but 5mm kep cropping up.

 

Jamie

Edited July 30, 2020 by jamie92208

[Barry O]

No one has mentioned (yet, I believe) placing the bogie pivot on ex NER locos in front of the pony truck wheel. It worked wonders for my A6. (a fellow modeller let me have a copy of an article about it, with the calculations involved)

 

I note some discussion about "using the same method as the real thing".. it may be the same method but, lots of things do not scale down (of course Gravity is the major one ). The idea pushed forward by the  S4 test track at shows used to be something along the lines of "with compensation our 08 shunter as shown, will be able to get over all irregularity on the track"  On the test plank an 06 suitably compensated could be driven up and down a deliberately undulating piece of track.. then over a large piece of woo (it may have been a Fleetwood-Shaw wooden sleeper). It scaled up to slightly bigger than a BR wooden sleeper.. show me the real 08 which can do that?

 

I have tried the S4 bogie control method - it just doesn't work for me. 

 

Baz

[Chuffer Davies]

18 minutes ago, Barry O said:

I have tried the S4 bogie control method - it just doesn't work for me. 

 

Baz

I tried it once and didn't get on with it either.   There are easier ways.

[Tony Wright]

6 hours ago, Headstock said:

 

Morning Tony,

 

I have to confess, it's not actually my suggestion.

Good evening Andrew,

 

 Beware of those who celebrate of ludditism and think it is clever.

 

Whose was it then?  Do tell.

 

Regards,

 

Tony. 

[Tony Wright]

6 hours ago, Chuffer Davies said:

Hi Chas,

As soon as I read Andrew's explanation of the benefits of side control I knew this age old argument would kick off again.  There are definitely two opposing camps here with only a few modellers taking the middle ground.  As those who have read my postings previously will know my approach to chassis building is definitely at the opposite end of the spectrum to that of Sir, although there is common ground even here when it comes to the importance of building the chassis square and making sure that the coupling rod centres are exactly aligned with the axle centres in the frames.  

 

When it comes to side control it is not incorrect for Tony to say that it is un-necessary  but I cannot agree that it offers no benefit.  A particular case in point for me where side control proved highly beneficial was for loco's shunting the yard on our Hungerford exhibition layout.  Initially I could not shunt into the rear siding in the goods yard using a small prairie's front buffers without buffer locking occurring.  As soon as I fitted side control to the front pony truck the problem was solved.  Before anyone suggests I could have restricted the side play on the front driven axle to achieve the same outcome, I'd already tried that. 

 

I can also say with confidence that side control on a bogie does definitely improve the passage of a locomotive through point work.  It is only a small incremental improvement, but an improvement none the less and I am very happy to spend an extra hour fitting side control for this small benefit.  It can also be the difference between needing to remove material from the back of the cylinders or not.  Tony says he is happy to do this as it can't be seen.  I personally hate doing this if I can avoid it.   

 

Not all layouts are suitable for models built with side control.  I anticipate that it is only suitable for, and you will get benefits with, models that are built to run on fine scale track, if you are using Peco points then the incremental benefit will be lost.  If your layout has curves tighter than 3ft here again I think you are expecting too much for a model with side control to work. Whilst I always ensure that the models I build will go round 2ft 6in radius I never run them in anger around anything under 3ft.

 

Fitting side control is not complicated but it does require the modeller to take the time to understand the mechanics of it.  If its not thought through it is unlikely to work (i.e. derailments will occur).  Here again I'm more than happy to take the time to think it through and it gets easier to get it right the more I do it. 

 

If you have a personal dislike of side control then don't do it, for me I see the benefit and I will continue to employ it for as long as I model.

 

Back to you Sir....

 

Frank  

As expected Frank,

 

A very well-reasoned 'argument'. 

 

I can do no better than to quote you.........

 

'Not all layouts are suitable for models built with side control.  I anticipate that it is only suitable for, and you will get benefits with, models that are built to run on fine scale track, if you are using Peco points then the incremental benefit will be lost.  If your layout has curves tighter than 3ft here again I think you are expecting too much for a model with side control to work. Whilst I always ensure that the models I build will go round 2ft 6in radius I never run them in anger around anything under 3ft.'

 

Regards,

 

Tony. 

 

[micklner]

48 minutes ago, Barry O said:

No one has mentioned (yet, I believe) placing the bogie pivot on ex NER locos in front of the pony truck wheel. It worked wonders for my A6. (a fellow modeller let me have a copy of an article about it, with the calculations involved)

 

I note some discussion about "using the same method as the real thing".. it may be the same method but, lots of things do not scale down (of course Gravity is the major one ). The idea pushed forward by the  S4 test track at shows used to be something along the lines of "with compensation our 08 shunter as shown, will be able to get over all irregularity on the track"  On the test plank an 06 suitably compensated could be driven up and down a deliberately undulating piece of track.. then over a large piece of woo (it may have been a Fleetwood-Shaw wooden sleeper). It scaled up to slightly bigger than a BR wooden sleeper.. show me the real 08 which can do that?

 

I have tried the S4 bogie control method - it just doesn't work for me. 

 

Baz

Have you a photo please ?

 

Any suggestions re the dreaded 0-4-4 Tank Loco, re the rear bogie set up ?

 

 

Edited July 30, 2020 by micklner

[Chuffer Davies]

6 minutes ago, micklner said:

Have you a photo please ?

 

Any suggestions re the dreaded 0-4-4 Tank Loco, re the rear bogie set up ?

 

 

I'll message you....

[Headstock]

25 minutes ago, Tony Wright said:

Good evening Andrew,

 

 Beware of those who celebrate of ludditism and think it is clever.

 

Whose was it then?  Do tell.

 

Regards,

 

Tony. 

 

Good evening Tony,

 

what makes you think it was singular?

[Barry O]

22 minutes ago, micklner said:

Have you a photo please ?

 

Any suggestions re the dreaded 0-4-4 Tank Loco, re the rear bogie set up ?

 

 

If I can get one I will send it. As far as 0-4-4 tanks..I only have a nicest G5 and it needs a new chassis.

 

Baz

[Headstock]

1 hour ago, Tony Wright said:

As expected Frank,

 

A very well-reasoned 'argument'. 

 

I can do no better than to quote you.........

 

'Not all layouts are suitable for models built with side control.  I anticipate that it is only suitable for, and you will get benefits with, models that are built to run on fine scale track, if you are using Peco points then the incremental benefit will be lost.  If your layout has curves tighter than 3ft here again I think you are expecting too much for a model with side control to work. Whilst I always ensure that the models I build will go round 2ft 6in radius I never run them in anger around anything under 3ft.'

 

Regards,

 

Tony. 

 

 

Not all layouts  are suitable for existing models built with side control, would make more sense. You can build a suitable system for specifically the criteria that Frank lays out. There are plenty of modelers on this very forum, who have sorted out the poor performance of the derailing Hornby L1, by adding side control. They are not finescale modelers and are running on peco point work and over curves tighter than three feet.

Edited July 30, 2020 by Headstock

[Tony Wright]

1 hour ago, Chuffer Davies said:

Hi Phil,  you are correct but there is one other element you are missing.  Unless the locomotive is right on the edge of being able to negotiate the radius of  the curve then there will be some lateral twist to play with.  Without any side control on the trailing axle the cab will swing out as far as it is able to.  If the trailing axle has side control fitted then this will encourage the loco to straighten up as far as it is able through the curve.  It’s all very subtle and I can hear Sir snoring in the background, but sadose like me love this stuff.  
 

Frank

 

 

Good evening Frank,

 

I'm not snoring.

 

It's all very fascinating. However, there's one thing I don't quite understand (only one I hear you all cry!). 

 

A loco body is a rigid, fixed length. Unless it's made of rubber, it doesn't flex. Thus, if one uses the bogie to effectively reduce the front overhang on a curve, then that surely must impact on the back end? I'm talking here of the likes of Graham's lengthy Prinny (though Thompson Pacifics have a potentially huge overhang at the front). If the front end tucks-in, then the back end must stick out further; mustn't it? 

 

Or, as usual, what am I missing?

 

When I laid out the fiddle yard roads on Little Bytham, particularly where they met Norman Solomon's scale-spaced scenic-side trackwork, I wanted the maximum front overhang to be present; to ensure passing vehicles didn't clout each other.

 

 

To this end, I used GREAT NORTHERN, the LNER loco with the longest overall wheelbase (excepting the Raven A2s), thus the one with the greatest potential overhang. A Pullman car, being the longest vehicle, was used to make sure there was sufficient clearance (the radius here is just less than 4'). 

 

Despite 60113's bogie just 'going along for the ride', I don't think the front overhang is excessive, though the rear end is a bit more extreme. 

 

Regards,

 

Tony. 

 

 

[sandra]

19 hours ago, pete55 said:

 

Hello Sandra,

I think t-b-g mentioned to you in a telephone conversation recently that the Anglo Scottish Car Carrier and Silver Fox are sat in a box under a bed here, and after a quick service are ready to return to Retford.

So when current circumstances allow I look forward to bringing it back home as it were!

 

Pete Hill

 

Pete,

That’s really kind, I would love to see the Anglo Scottish car carrier back on Retford where I think it belongs.

 

Unfortunately we may have to wait for things to improve but it would be great to have it back.

Sandra

[Chuffer Davies]

30 minutes ago, Tony Wright said:

 

 

Good evening Frank,

 

I'm not snoring.

 

It's all very fascinating. However, there's one thing I don't quite understand (only one I hear you all cry!). 

 

A loco body is a rigid, fixed length. Unless it's made of rubber, it doesn't flex. Thus, if one uses the bogie to effectively reduce the front overhang on a curve, then that surely must impact on the back end? I'm talking here of the likes of Graham's lengthy Prinny (though Thompson Pacifics have a potentially huge overhang at the front). If the front end tucks-in, then the back end must stick out further; mustn't it? 

 

Or, as usual, what am I missing?

 

When I laid out the fiddle yard roads on Little Bytham, particularly where they met Norman Solomon's scale-spaced scenic-side trackwork, I wanted the maximum front overhang to be present; to ensure passing vehicles didn't clout each other.

 

 

To this end, I used GREAT NORTHERN, the LNER loco with the longest overall wheelbase (excepting the Raven A2s), thus the one with the greatest potential overhang. A Pullman car, being the longest vehicle, was used to make sure there was sufficient clearance (the radius here is just less than 4'). 

 

Despite 60113's bogie just 'going along for the ride', I don't think the front overhang is excessive, though the rear end is a bit more extreme. 

 

Regards,

 

Tony. 

 

 

Hi Tony,

you are as always correct.  I failed to state a point in my earlier explanation that I have just realised and which possibly better describes the point I was trying to make.   On the 4ft radius I suspect you can slide the loco laterally because the radius is still quite gentle by model railway standards.    Without side control the loco will tend to prefer the outside of the curve, with side control fitted front and back the loco's driving wheels will be encouraged to follow the inside of the curve therefore you will get a small difference in where the locomotive sits on the track. 

 

Having said all that and whilst it is an interesting academic discussion, in the particular case you have raised it is of no consequence.  

 

Regards,

 

Frank  

[davefrk]

44 minutes ago, sandra said:

Pete,

That’s really kind, I would love to see the Anglo Scottish car carrier back on Retford where I think it belongs.

 

Unfortunately we may have to wait for things to improve but it would be great to have it back.

Sandra

 

Hi Sandra, I have the J52 I built to shunt the yard if you wish that back on Retford, It's been serviced and is ready to re-enter service, It's actually a bit of a stranger on my layout Wharfeside so it may as well move back to Retford.

I don't know if you remember me, I'm one of the 'Scots Gits' as Roy christened us and I usually worked the Babworth box when I could get down from Glasgow.

 

All the best to you and Retford.

Dave Franks.

[pete55]

51 minutes ago, sandra said:

Pete,

That’s really kind, I would love to see the Anglo Scottish car carrier back on Retford where I think it belongs.

 

Unfortunately we may have to wait for things to improve but it would be great to have it back.

Sandra

 

No problem, it will return!

[pete55]

Just now, davefrk said:

 

Hi Sandra, I have the J52 I built to shunt the yard if you wish that back on Retford, It's been serviced and is ready to re-enter service, It's actually a bit of a stranger on my layout Wharfeside so it may as well move back to Retford.

I don't know if you remember me, I'm one of the 'Scots Gits' as Roy christened us and I usually worked the Babworth box when I could get down from Glasgow.

 

All the best to you and Retford.

Dave Franks.

 

Sounds like we need some of your decent loco lamps for Tony to install on locos too!!

[Tony Wright]

One more recent Retford picture to finish the day.

 

And, what a wonderful day of comments. Many, many thanks to all.....................

 

 

A rigid Retford V2 waits for the road on a short cement train.

 

Buccaneer John's wonderful houses in West Carr Road are crying out to be completed....................... And, his footbridge in the background (to feature in close-up soon) is magnificent. 

 

 

[bbishop]

Bogie Engines The oscillation of bogies at high speeds is considerable, and is due to the centre pin of the bogie being central between the leading and trailing axles.  To obviate this difficulty I place the pin two inches out of centre, and by this means secure a steady running bogie, and practically do away with he oscillation and side hammering on the rails, and the lurching of the engine when passing round curves.

 

A quote from Dugald Drummond in 1911.