Chassis kits for CSB

This section allows guests to comment or ask questions. Posts from guests require explicit approval (which generally takes a day or so), before they appear, so that we can prevent unwanted spam.
proto87stores

Chassis kits for CSB

Postby proto87stores » Sun Aug 11, 2019 3:53 pm

Just a few basic already proven fact checks:

There is no need for a fixed axle on any steam locomotive wheel arrangement using either springing or full equalization. Even for 0-4-0's . See the 4 point wagon suspension test video posted earlier for confirmation.

Any form of wheel springing suspension statically and dynamically alters the weight carried on the wheel when going over uneven, bumpy or twisted track. (Hooke's Law). Correctly designed wheel equalizing suspension does not. Nadal's formula relies on wheel carrying weight always being greater than the minimum value. Hence wheel springing in the absence of excess of the necessary minimum wheel carrying weight is a higher derailment risk than equalization at the same weight.

The actual and perceived "smoother running" of a "sprung" vehicle can easily be achieved by soft springing the body to chassis mounting, regardless of (as well as instead of) soft springing the wheel suspension system. See Ralph Nader - "Unsafe any speed" report on USA automobile safety.

Since the CSB wires must slide/rotate continuously through the mounting clips to operate at all, they are as much a partial longitudinal equalization wheel suspension system (AKA compensation) as they are a wheel springing system. At least for the 0-4-0 and 0-6-0 wheel arrangements. Other CSB fitted driving wheel arrangements,e.g. x-8-x and greater, however cannot provide correct equalization movement and direction.

Generally, CSB suspension (one continuous wire) implementation is only practical for fixed frame driving wheels of multi-wheel arrangements. Additional traditional methods are still needed for suspending bogie and pony truck wheels, for even the simplest and shortest driving wheel arrangements.

Andy

Dave Franks
Posts: 41
Joined: Tue Apr 16, 2019 9:02 am

Re: Chassis kits for CSB

Postby Dave Franks » Sun Aug 11, 2019 9:34 pm

Quote <Other CSB fitted driving wheel arrangements,e.g. x-8-x and greater, however cannot provide correct equalization movement and direction.>

Sorry but once again it has to be pointed out to you that many of us find CSB's work very well and that includes locos with 8 driving wheels as commented on by a number of my friends on seeing an 8F 'gliding' along with 60 wagons.

Dave Franks.

proto87stores

Re: Chassis kits for CSB

Postby proto87stores » Mon Aug 12, 2019 3:29 am

<Other CSB fitted driving wheel arrangements,e.g. x-8-x and greater, however cannot provide correct equalization movement and direction.>

Sorry but once again it has to be pointed out to you that many of us find CSB's work very well and that includes locos with 8 driving wheels as commented on by a number of my friends on seeing an 8F 'gliding' along with 60 wagons.

Dave Franks.


The somewhat simplified description of CSB stands for Continuous, Springy, Beam. Since it is supported by a fixed pivot point between each horn block , it has to be considered as several springy beams joined end to end. And beams that pivot on a fulcrum are the close equivalent of see-saws. Push one end down, the other end MUST go up. If the beam is springy, and the riders are heavy, then the see saw bends under load FIRST until the see saw supports both riders statically closer to the ground. But it still works as the same see-saw and if one rider pushes up, the other rider will go lower, just as before, and by the same difference. Find some spare children and try it in your garden with planks of different (but adequate) strengths ;)

The portions of CSB at each support are springy beam sections that act like springy upside down see-saws with their fulcrum at the support. So the effect of pushing up one wheel on a bump pushes the adjacent wheel(s) down harder on the track. Which is good :) It's a crude form of equalization. But, because the sections are flexibly joined to the next, the equalizing effect is more complex and is reduced as it passes further on to the wheel after the immediately adjacent wheel, and so on. But it is obvious that coupling multiple see-saws end to end means that the riders at the alternate couplings are going to be moving in OPPOSITE directions. Rider 1 up, rider 2 down, rider 3 up, etc.

And when you use a CSB on a model locomotive, the alternate, opposite movement occurs on that too.

I have included some simplified diagrams below of an 0-8-0 arrangement to make that movement effect, and it's negative consequence more obvious. And to be positive, have finally provided a simple solution to make it work almost perfectly.

Image

Here we see the normal static position of an 8 coupled CSB on flat track. I've approximated the curves of the wire to save my drawing and calculation time.

Image

Now I've raised wheel # 1 as though it has ridden up onto a bump. I've simplified the wire beam shape even more as linked straight lines, as I just want to show that the beam sections pivot to take up the wheel (see-saw and rider like) movement. But now the problem with wheel # 3 and #4 becomes apparent. What works for an 0-6-0 for wheel # 3 as the reverse of wheel #2, goes wrong for wheel #4 in a an 0-8-0, because wheel #3 is trying to lift up from the track between wheel # 2 and wheel # 4. Obviously sufficient weight of the loco will force all the wheels down on to the flat portion of the track, by forcefully bending the wire against its alternating tendency. But that means the individual wheel weights will be increased or reduced incorrectly for optimum track holding.

Image

Here I've tilted the chassis to compensate for the bump so that the natural position of the wheels #1, #2 and #4 rest on the track as they would normally. But it is clear now if the loco weight was very light, that wheel #3 would actually being lifted by the reverse equalization, instead of beng placed firmly down between wheels # 2 and #4

Image

And here is the simple and completely effective solution. All that is needed is to break the CSB into two completely separate CSB's. The the equalization and weighting happens correctly between wheels #1 ands #2, followed by separate correct equalization between wheels #3 and #4. In fact this would become the correct construction for any of dual CSB's, dual springy beams, or dual rigid beams.

Andy




.

User avatar
Will L
Posts: 1666
Joined: Sun Jul 20, 2008 3:54 pm

Re: Chassis kits for CSB

Postby Will L » Mon Aug 12, 2019 11:20 am

proto87stores wrote:... Generally, CSB suspension (one continuous wire) implementation is only practical for fixed frame driving wheels of multi-wheel arrangements. Additional traditional methods are still needed for suspending bogie and pony truck wheels, for even the simplest and shortest driving wheel arrangements.


Generally I agree with that, though I am slowly working my way through a F6 (2-4-2T) with all 8 wheels on the CSB, with a weight distribution of 60% on the drivers and 40% on the carrying wheels (Ok yes only when static Andy). We'll see how I get on.

I'm with Dave by the way, I started by CSB career with a 2-8-0 which guides along a treat, nobody seems to have told it it has theoretical performance problems.

User avatar
grovenor-2685
Posts: 3178
Joined: Sun Jun 29, 2008 8:02 pm

Re: Chassis kits for CSB

Postby grovenor-2685 » Mon Aug 12, 2019 11:32 am

Obviously sufficient weight of the loco will force all the wheels down on to the flat portion of the track, by forcefully bending the wire against its alternating tendency. But that means the individual wheel weights will be increased or reduced incorrectly for optimum track holding.

Andy, do you really want to rehash all this yet again when those of us using CSBs find that it works just fine. And sufficient weight is a prerequisite for any springing system to work. The size of track irregularitie we are working with is small so the wheel unloading is not enough to cause a problem, Nadal is happy!
Regards

bobwallison
Posts: 55
Joined: Mon Jul 12, 2010 9:42 pm

Re: Chassis kits for CSB

Postby bobwallison » Mon Aug 12, 2019 12:31 pm

proto87stores wrote:Any form of wheel springing suspension statically and dynamically alters the weight carried on the wheel when going over uneven, bumpy or twisted track. (Hooke's Law). Correctly designed wheel equalizing suspension does not.


Completely agree in the case of a vehicle at rest on uneven track, but what about the dynamic case - for example a vehicle moving on level track as it encounters a local dip? With a compensated vehicle, for all the wheels to remain in contact with the rail the whole mass of the vehicle has to move downwards to push the wheel into the dip whereas, like all moving objects, it really wants to keep going at constant velocity in a straight line. Earth's gravitational pull will accelerate the vehicle downwards, but it won't happen instantaneously and the distribution of loads in the meantime is uncertain. In contrast, if all the wheels are individually sprung, it is only one wheel (and a proportion of the axle weight) that needs to be pushed into the dip and because the inertia is low, that will happen relatively quickly and with minimal impact on the path and velocity of the vehicle as a whole.

One could dust off one's A-level physics and do the sums, but really, what is the point? We have all seen compensated vehicles performing really well; ditto CSB vehicles and those with individual springing. An individual's preferences will be determined partly by the quality of their track and partly by their own perception of movement. What we should be wary of, though, is applying the rules of static equilibrium to a very dynamic condition in an attempt to promote one suspension system over the others.

Bob

proto87stores

Re: Chassis kits for CSB

Postby proto87stores » Mon Aug 12, 2019 6:12 pm

Andy, do you really want to rehash all this yet again when those of us using CSBs find that it works just fine. And sufficient weight is a prerequisite for any springing system to work. The size of track irregularitie we are working with is small so the wheel unloading is not enough to cause a problem, Nadal is happy!
Regards


My explanation diagram and easy answer applies to the specific x-8-x case.

Why would anyone deliberately construct something that requires so much time and effort with an obvious fault when it is as easy, fast and cost free to make the same design better? And then even instruct others to follow in their less effective footsteps? And yet the fix even works on existing installations!

Andy

proto87stores

Re: Chassis kits for CSB

Postby proto87stores » Mon Aug 12, 2019 6:38 pm

Completely agree in the case of a vehicle at rest on uneven track, but what about the dynamic case - for example a vehicle moving on level track as it encounters a local dip? With a compensated vehicle, for all the wheels to remain in contact with the rail the whole mass of the vehicle has to move downwards to push the wheel into the dip whereas, like all moving objects, it really wants to keep going at constant velocity in a straight line. Earth's gravitational pull will accelerate the vehicle downwards, but it won't happen instantaneously and the distribution of loads in the meantime is uncertain. In contrast, if all the wheels are individually sprung, it is only one wheel (and a proportion of the axle weight) that needs to be pushed into the dip and because the inertia is low, that will happen relatively quickly and with minimal impact on the path and velocity of the vehicle as a whole.

One could dust off one's A-level physics and do the sums, but really, what is the point? We have all seen compensated vehicles performing really well; ditto CSB vehicles and those with individual springing. An individual's preferences will be determined partly by the quality of their track and partly by their own perception of movement. What we should be wary of, though, is applying the rules of static equilibrium to a very dynamic condition in an attempt to promote one suspension system over the others.

Bob


In the case of the x-8-x, I'm actually proposing an obvious CSB problem with a no brainer CSB fix. I don't see how that is at all controversial?

As to generally promoting a modernized version of Mike Sharman's idea, suppose the assembly time of a typical chassis is reduced by 90% and all the necessary alignment and working accuracies completely incorporated in the parts supplied? Should I use it for Proto:87, but keep it a secret from only the Scalefour membership?

Andy

proto87stores

Re: Chassis kits for CSB

Postby proto87stores » Sat Aug 17, 2019 11:24 pm

bobwallison wrote:
proto87stores wrote:Any form of wheel springing suspension statically and dynamically alters the weight carried on the wheel when going over uneven, bumpy or twisted track. (Hooke's Law). Correctly designed wheel equalizing suspension does not.


Completely agree in the case of a vehicle at rest on uneven track, but what about the dynamic case - for example a vehicle moving on level track as it encounters a local dip? With a compensated vehicle, for all the wheels to remain in contact with the rail the whole mass of the vehicle has to move downwards to push the wheel into the dip whereas, like all moving objects, it really wants to keep going at constant velocity in a straight line. Earth's gravitational pull will accelerate the vehicle downwards, but it won't happen instantaneously and the distribution of loads in the meantime is uncertain. In contrast, if all the wheels are individually sprung, it is only one wheel (and a proportion of the axle weight) that needs to be pushed into the dip and because the inertia is low, that will happen relatively quickly and with minimal impact on the path and velocity of the vehicle as a whole.

One could dust off one's A-level physics and do the sums, but really, what is the point? We have all seen compensated vehicles performing really well; ditto CSB vehicles and those with individual springing. An individual's preferences will be determined partly by the quality of their track and partly by their own perception of movement. What we should be wary of, though, is applying the rules of static equilibrium to a very dynamic condition in an attempt to promote one suspension system over the others.

Bob


One if the "what for" points is that making chassis construction simple, fast and impossible to get wrong, would likely steadily increase the membership of the Society tenfold. Maybe even start a trend of there gradually being easy to manufacture RTR P4 equipment. In the case of the "point" of an un-split CSB used in x-8-x wheel arrangements, I'll refer to this recent post:

Why make something simple when with a little effort you can make it complicated. :D :D

Terry Bendall


Two other less than "A" level understanding things to be aware of are:

1: There is no different "dynamic case". Any dynamic effect due to body inertia and/or especially energy storage in added springs, is a progressive effect that only occurs in some proportion to increasing speed. In the case of slow running Protofour layouts, it's highly unlikely that any performance difference from the static equilibrium positions is noticeable.

2: A CSB mounted wheel cannot drop into a dip at all, unless simultaneously end-on pushing its now excess length springy wire beam back through all the various horn block and wire supports holding it. That has far more inertia to overcome than a simple per wheel spring. In any case, no suspension system has to directly lift the central whole weight of the vehicle. They all just lever their force against their particular distance and direction from the c of g and the diametrically opposite wheel(s).

I did cover other points in my two earlier missing posts. Further information regarding the N7 chassis is most likely to appear on the future forum at http://www.ismrsa.org/forum

User avatar
grovenor-2685
Posts: 3178
Joined: Sun Jun 29, 2008 8:02 pm

Re: Chassis kits for CSB

Postby grovenor-2685 » Thu Aug 29, 2019 2:11 pm

So you do want to rehash it :)
One if the "what for" points is that making chassis construction simple, fast and impossible to get wrong, would likely steadily increase the membership of the Society tenfold. Maybe even start a trend of there gradually being easy to manufacture RTR P4 equipment.

For my part I'll believe it when I see it, I suspect I'm not alone. :) How many years now have you been talking of this wonder?

Dave Franks
Posts: 41
Joined: Tue Apr 16, 2019 9:02 am

Re: Chassis kits for CSB

Postby Dave Franks » Thu Aug 29, 2019 5:38 pm

Unbelievable!!!!

Proto87stores

Re: Chassis kits for CSB

Postby Proto87stores » Thu Aug 29, 2019 8:15 pm

I don't want to bore anyone with the details, but the two major medical events with my immediate family, the long term care giving and the subsequent emotional consequences, effectively shut down my design efforts between 2009 and 2018. I'm just about able to function normally now, although the 2018 factory relocation still needs much work. The replacement new test track is only at a very early stage.

As to the ease of construction, completely reliable functionality and prototypically extemely accurate, final appearance , almost all the track products I designed before 2009 are officially banned from NMRA competitions and their "MMR" qualifying coursework, for those very reasons.

Andy

User avatar
zebedeesknees
Posts: 46
Joined: Mon Jul 12, 2010 5:15 pm

Re: Chassis kits for CSB

Postby zebedeesknees » Fri Aug 30, 2019 11:03 am

Will and Dave should call their 2-8-0s 'Bumble Bees'... some blinkered theorists say that they can't fly!

User avatar
Horsetan
Posts: 946
Joined: Tue Jul 29, 2008 9:24 am

Re: Chassis kits for CSB

Postby Horsetan » Sat Aug 31, 2019 4:14 pm

Dave Franks wrote:Unbelievable!!!!


Image
That would be an ecumenical matter.

proto87stores

Re: Chassis kits for CSB

Postby proto87stores » Sat Aug 31, 2019 4:46 pm

With regard to fitting CSB's to the usual 0-6-0 wheel arrangement, although if course unnecessarily for EM.

Shouldn't the wheels on a model J52 fit into the splashers?

e.g. Image

Is it the suspension that is altering the footplate height? What's the weight distribution of the wheels on the far side?

Andy

bobwallison
Posts: 55
Joined: Mon Jul 12, 2010 9:42 pm

Re: Chassis kits for CSB

Postby bobwallison » Sat Aug 31, 2019 6:10 pm

proto87stores wrote:In the case of the x-8-x, I'm actually proposing an obvious CSB problem with a no brainer CSB fix. I don't see how that is at all controversial?

The clue is in the quote I included in my previous post, where you claim as "a basic proven fact" that equalising suspension does not dynamically alter the weight distribution on uneven track.

proto87stores wrote:There is no different "dynamic case".


Oh, come! So our models don't obey the normal laws of physics? I agree that the effects might not be noticeable, but the same could be said of sprung suspension on all but the worst track. And not all of us run our trains at crawling speed.

When I asked "what is the point", I was querying the value of grossly simplified analyses (friction in bearings? forces in coupling rods?) when there is such a growing body of practical experience of the various forms of suspension. I cannot recall anyone who has tried springing who then reverted to equalised suspension because it worked better or was significantly easier.

Bob

davebradwell
Posts: 119
Joined: Fri Jan 18, 2019 3:48 pm

Re: Chassis kits for CSB

Postby davebradwell » Sat Aug 31, 2019 6:13 pm

.......and quieter.

DaveB

Dave Franks
Posts: 41
Joined: Tue Apr 16, 2019 9:02 am

Re: Chassis kits for CSB

Postby Dave Franks » Sat Aug 31, 2019 8:41 pm

Yes dave, soooo much quieter.

Dave Franks. :thumb

proto87stores

Re: Chassis kits for CSB

Postby proto87stores » Sat Aug 31, 2019 10:07 pm

bobwallison wrote:The clue is in the quote I included in my previous post, where you claim as "a basic proven fact" that equalising suspension does not dynamically alter the weight distribution on uneven track.


That what equalizing means. The weight per wheel is not altered due to the suspension wheel height positioning changing.

proto87stores wrote:There is no different "dynamic case".


bobwallison wrote:Oh, come! So our models don't obey the normal laws of physics? I agree that the effects might not be noticeable, but the same could be said of sprung suspension on all but the worst track. And not all of us run our trains at crawling speed.


I said the opposite. Of course the same laws apply. There is not a separate, different case. But when calculating the effects of moving vehicle body inertia, the value of "a" in F=ma is zero when stationary and only increases gradually as the vehicle speed increases.

bobwallison wrote:SNIP I cannot recall anyone who has tried springing who then reverted to equalised suspension because it worked better or was significantly easier.


The design of US freight cars initially copied the early UK 4 wheel sprung designs, but very soon after switched to the US standard design of two equalized wheel trucks (bogies) under sprung bolsters. That basic design with only constructional improvements continues through the present day. It also became the standard method of support and suspension of US 8 wheel tenders for all but the very largest US steam locomotives. No suspension interaction between axles 2 and 3 was ever added (or deemed necessary). And of course most US Steam locomotive chassis had equalization as well as basic wheel springing

Andy

Dave Franks
Posts: 41
Joined: Tue Apr 16, 2019 9:02 am

Re: Chassis kits for CSB

Postby Dave Franks » Sun Sep 01, 2019 9:23 am

Proto87stores wrote:I don't want to bore anyone with the details,
Andy

Too late for that....

And, you state CSB in unnecessary in EM.... So you think these people don't want smooth silky running with reliable pickup on their models?

The J52 was a quick job so the over large splashers were left as they are and they do line up by the way. Ride height is correct to spec so stop trying to pick holes.

You also state:- Why would anyone deliberately construct something that requires so much time and effort with an obvious fault when it is as easy, fast and cost free to make the same design better? And then even instruct others to follow in their less effective footsteps? And yet the fix even works on existing installations!
Sorry but I've looked everywhere on my models and those built for other people and I still can't find the 'obvious' fault, they run well, stay on the track, are very stable through pointwork but then so is independent suspension like Dave Bradwells so why would I go back to beams.

One other point, I believe too that the friction of the wire moving through the chassis anchors induces some resistance rather like a shock absorber to lessen any body roll, this though maybe rubbish as the movement of the wire in the anchors is immeasurable as our track is as flat as a mill pond compared to what you are obviously used too.... And as to your diagram ?????
Now we'll all get back to modelling without all the guff whilst you go and study the CLAG CSB pages.

And you wonder why I've blocked your email address from my mailbox, my products will stay as they are but thanks for your advice. :)



Dave.

http://www.lanarkshiremodels.com
Last edited by Dave Franks on Sun Sep 01, 2019 10:02 am, edited 1 time in total.

User avatar
Will L
Posts: 1666
Joined: Sun Jul 20, 2008 3:54 pm

Re: Chassis kits for CSB

Postby Will L » Sun Sep 01, 2019 9:51 am

davebradwell wrote:.......and quieter.

For some reason I have never used that as a (another) reason for favouring springing. But your right

User avatar
grovenor-2685
Posts: 3178
Joined: Sun Jun 29, 2008 8:02 pm

Re: Chassis kits for CSB

Postby grovenor-2685 » Sun Sep 01, 2019 9:59 am

I said the opposite. Of course the same laws apply. There is not a separate, different case. But when calculating the effects of moving vehicle body inertia, the value of "a" in F=ma is zero when stationary and only increases gradually as the vehicle speed increases.

That formula does not have any direct relationship to speed, I don't see the relevance. Presumably you mean vertical F and a which the springs act to keep to tolerable levels but which can become very high if unsprung.
However, as I said earlier, why rehash all this which we have gone through before?
Many of us understand the effects on a model of rigid, equalised and sprung suspensions and combinations thereof and have built and operated models with various arrangements and have decided which we prefer. No amount of theory will change our minds, practical demonstration might. So do it and show it off :) .

High Level Kits
Posts: 36
Joined: Tue Oct 02, 2012 8:37 am

Re: Chassis kits for CSB

Postby High Level Kits » Mon Sep 02, 2019 9:51 am

OK, I've just done a practical demonstration to reassure myself I’m not a jackass selling faulty gear.

On an inverted six-coupled, I yanked the middle set of drivers up and down for their full travel. The outer wheelsets twitched very slightly, nothing more.

This suggests to me that the CSB system is not that far from being independent suspension, but the small amount of interaction between the wheelsets, means it's effectively self levelling and self-adjusting. I see this as a bonus.

Thinking of the system with the emphasis on the beam aspect as opposed to the springing is misleading.

This ‘ease of construction’ thing is a novel idea though - what’s that all about?... :?

User avatar
Noel
Posts: 1145
Joined: Wed Jun 23, 2010 1:04 pm

Re: Chassis kits for CSB

Postby Noel » Mon Sep 02, 2019 11:34 am

proto87stores wrote:But when calculating the effects of moving vehicle body inertia, the value of "a" in F=ma is zero when stationary and only increases gradually as the vehicle speed increases.


Acceleration is certainly zero when the mass is stationary, but is also zero at any constant speed. It may mean that no force is being applied, but may also mean that the resultant of multiple forces being applied is zero. Force and acceleration in this equation are, incidentally, vectors [i.e. have direction as well as magnitude] and if more than one force is involved the resultant may be in any direction, not just the initial direction of travel.

Acceleration may change gradually as the speed changes, but may be constant as the speed changes [if you read Science Fiction, contemplate the acceleration of generation ships] and any change can be positive or negative, depending on the forces involved. However, there is nothing to require a gradual change; if a force is applied abruptly [e.g. a vehicle hitting a brick wall, or an aircraft being catapulted or a wheelset hitting an obstruction] at least one of the rate(s) of acceleration involved will change abruptly.
Regards
Noel

bobwallison
Posts: 55
Joined: Mon Jul 12, 2010 9:42 pm

Re: Chassis kits for CSB

Postby bobwallison » Mon Sep 02, 2019 2:54 pm

grovenor-2685 wrote:No amount of theory will change our minds, practical demonstration might. So do it and show it off :) .


Hear, hear, especially when the theory takes no account of all the additional factors that come into play for moving vehicles, as mentioned above. (OK, I will agree with Andy that they are additional factors and not different ones.)

I eagerly await the arrival of a 9F chassis kit that can be assembled quickly and without possibility of error, as hinted at in another thread.

Bob


Return to “Guest Book”

Who is online

Users browsing this forum: No registered users and 2 guests