Modular exhibition layout

[IanT]

Still looking at it Ralph.

Derek, it occurs to me that I have probably not explained one key part of what we've been considering. We have the notion of 'Standard' and 'Custom' C3 modules. The standard modules are essentially simple straight and curved track components and are fairly closely defined. Custom modules (sections if you wish) can be just about anything you want them to be, provided they have at least one C3 compliant connection point. They ideally will be a multiple of the standard modular length and can be split up internally any way (or to any length) you might wish. If you want to 'through' run, then the custom module will need a C3 connection at each end - but those ends can be 20 "length multiples" apart if you want them to be.

So I'm assuming that people will build the level of 'complexity' or prototypical accuracy they want within their own 'custom' sections but will be able to connect them together using simpler (C3) track modules. Our current exhibition railways would qualify as custom modules for instance - provided they have a C3 connection point. So at it's simplest, we could connect existing G3 layouts end-to-end for instance.

Regards,


IanT

[MikeWilliams]

Ian.T,

Since you asked for opinions, mine is that rail comes in 3ft lengths and I see no good reason to change from that.  Derek makes a good point, but the boards neeed to be as long as can be reasonably handled and for me that's 3ft.

Even our government seem to be stepping back from full decimalisation in some ways.

Mike

[Derek King]

Ian,

Returning to the subject of a "Modular Exhibition Layout", as per the Spur II example (or probably more simply a continuous "Test Track" circuit as often seen at O Gauge Shows), what options have you considered for supporting these short modules and at what height - both important points for standardisation.

The latter point is of particular importance if the modules are to be also used for joining 2 separately built Exhibition layouts together.

Derek.

[IanT]

All the European Modular systems (that I've looked at Derek) define it as 1 metre (as measured from floor to rail top - plus or minus 25mm). The US Standards (NMRA) generally use 40" (although 'S' & '0' are set at 42", and tinplate at 36"). However, 40" is 1016mm - so falls within the 1m +/- 25mm range.

So we are planning to use 1 metre +/- 25mm as the standard but we are not going to define the "mechanics" of the legs. Most people seem to use the traditional two upright legs, with cross bracing. I notice that some of the Spur II guys are using a very neat 'table' system that seems to be made of aluminium (see the photos on the link at the start of this thread).

I've been experimenting with a single folding leg - that is kind of hard to describe but the main body is an "I" shape, with two legs at one end that fold out to form an "A". The top of the "I" is about 150mm across and has two 10mm holes that match the C3 connection. They attach to the baseboard using the same bolts that connect the modules together. When folded they are about 600 mm long. You can see the top of one (but not the legs unfortunately) in the AGM photo somewhere in the thread below. I simply used it (on the outside of the module) to hold a makeshift ply "buffer" to ensure the loco couldn't roll off the end of the track.

[Kalinowski]

Hello Ian,

I have to agree with Mike Williams. Cliff Barker's (CB) web site show that his stainless steel rail modules are 3 feet or 6 feet long. If the Associations' brass rail is 3 feet long and so is CB also, why go metric?  If we were going to travel to Europe and join up with a German group at a show it might make some sense, but I doubt that this would be so in the near future.

If the European standard module is 1 metre, my response is so what! As the UK and Germany are the only 2 European countries out of the 27 Member states with a substantial following modelling in G3, lets confirm to what the UK needs.

The modules that I made, that you now have, were all 6 feet long because with portable lengths you don't want fiddly end bits ( 6.4 or 3.2 inches) all over the place. I had to drive with the 6 foot lengths stick out of the front car window!
Stacking inside a car is critical and 3 feet is OK for my own car, but not 1 metre.

Perhaps the "Short standard length" should be 3 feet and any other "Non standard length" can be whatever the circumstance require.
regards

[John Candy]

So far, score seems to be Imperial 4 : Metric 2 but I suspect there is some way yet to go!

No mention yet of radii.
If the ultimate aim is to join umpteen sections in an exhibition hall, then does there not need to be a specified optimum radius (or radii)? It is unlikely that a straight run of 60 or 80 ft is going to be available, similarly 20ft radius curves are not a practical proposition.

The 'G' scale curves (including those in the 'Spur 2' photos) are very tight, perhaps as little as 4ft radius (or whatever in Metric) and that would not be workable for a 'proper' G3 layout, in fact most locos and rolling stock would not be able to negotiate much less than 8ft and would be happier with 15!

[MikeWilliams]

Interested to read Ian.T's specified height of 1 metre + or - 25mm.  I assume that means a nominal 1m but provide at least 25mm adjustment up and down?

John is right about standard radii if the idea is taken a stage further with the potential to join boards into an oval.  I know Ralph and Ian have discussed this and the equally important chord or baseboard length for curves.  Personally I'd go for 12ft or 15ft radius.

Mike

[Andy B]

If we assume that we will generally use curved sections to give a 90 degree bend, then the exact radius doesn't actually matter provided there are 'make-up' straight sections at the ends so that the overall quadrant adheres to the 'standard' module size (whatever that is defined as).
Several people have suggested that they could make one (removable) section of their home line to be C3 compatible, and this could work in my proposed line too - but due to their particular constraints they may not be able to use, say 12' radius, but can use 11' 6" - so in their own line they just use their basic boards, and have a couple of 6" extensions to use when joining up with others.

Now, if we want a 'real' railway with transition curves and superelevation, it gets a bit more interesting......... 

Andy

[cabbage]

I think people are starting to get a little confused here...

The length of a C3 Module is 900mm.
The width of a C3 module is 150mm
The height from floor to rail head is 1000mm +/- 25mm

The size is based on the fact that most common materials (eg wood) are now sold in multiples of 300mm. Thus it made sense to design a module based on a standard length of timber.

VIZ:

A 2400mm length of PSE timber 69mm x 18mm would cost £3.21p from Wickes. This gives me two sides at 864mm, two ends at 150mm, three internal cross pieces of 114mm -leaving you with an off cut 30mm long... I then glue/nail a piece of 3mm thick hardboard on top of it. One £4.37p sheet provides the tops for eight C3 modules. The rail head then sits 16mm from the hardboard. The height of the completed C3 module is (16+3+69) = 88mm. The legs would not be a metre long as the distance from the bottom of the C3 module to the floor would never exceed 937mm.

As to radii and chord distances... I personally favour a curve fabricated on an 18 sided polygonal base -as this makes both the maths and construction easier. There are a few "perfect radii" and "perfect chords" but the first of the perfect radii start at roughly 3.5 metres or 11 feet 6 inches radius. Any "tighter" than that and we could get into some dire constructional stress. I should know as my curves are going to have to be 2.3 metres or 7 feet 6 inches radius and I have had to roll the rail in slips and "jig build" the track to take that sort of bend. As it is I still believe that "Hillmans Railclamps" will have to be used to connect the sections of my curves.

I don't have the C3 spec document on this server, (mine is two time zones west), but I seem to recall a radius system based on multiples of 300mm(?) Which would be handy as the first perfect chord works out as a rough radius of 3.8 metres...

regards

ralph

[IanT]

At the risk of jumping some guns here (I'm awaiting some claifications from Ian's Spur II friend (Torsten) and also I'm mapping out some possible combinations using CAD - I would make the following comments.

Like it or not, the UK (and most of the world) have gone metric. My sons for instance do not "do" Imperial. Already metric fittings are the only ones commonly available. I'm going to specify a metric bolt (not a 3/8ths one) for a mechanical connection for instance. If we are trying to create "Standards" then let's do it in something that is as current as we can make it. It is more likely to be used, and less likely to date.

Cabbage's original point to me was that it did not make sense to "mix" measurements and having thought about it, I agree. The fact that rail length is 3' currently is also really a fairly short term issue, IF we are planning standards that will have a life of 10 to 20 years and possibly more. Both the Society and CB can move to a metric rail length over time - and it's really not a big issue to use 3' in the meanwhile. Two of my 3' sections can have a 171mm extension screwed on one end, and hey presto - I have a 2 metre module. Or as Cabbage argues, use 900mm and cut 14.4mm off the rail (just over 1/2")

Most rail will be continue to be consumed building garden railways and 'custom' sections anyway, where the rail length doesn't matter too much at all in practice. The moment you start to build turnouts, you always end up with all sorts of odd lengths, both used and left over (at least I do). I would also point out that whatever radii curve you decide to use, you will never have a perfect length to fit them, as they will be a 'radial' length (as {I think} Cabbage points out) and my less informed view is that one rail is always longer than the other anyway.

So I'm trying to take a long view and get a solid solution. I don't think we will "join up" with the Spur II guys - but why rule it out? Who knows what will happen - visits to their Schenklengsfeld event - why not?

Oh, and Andy - who said we couldn't do transistions - NEM 113 covers this, although they call them "Easements" . Just seen Cabbage has posted in from abroad. Just to say the Spur II minimum radius for "mainline" is 3000mm and 1500mm for light/industrial railways "in exceptional cases" 

Glad to see some interest   

[IanT]

Sorry, don't mean to over-do this topic but I've just had an email back from my Spur II friend, Torsten, which I though might be of interest to recent posters here.

The Spur II standard gauge module definition (M24) doesn't give a recommended module length (unlike their NG M22 standard of 660mm). This was one of the questions I asked Torsten to clarify for me. His reply was a bit of a surprise, given that all the module standards I've looked at do define this aspect of their modules.

Torsten say's it's not defined in M24, because it's up to Spur II Members to decide the module length that best suits their transport requirements.....

Well, my interest in Spur II standards was basically because they are (in so many respects) the same as  Gauge 3, and they are by far the nearest thing to us in their design requirements (N & Z gauge are a bit removed from G3 after all). It's also pretty clear from the photos of their annual Schenklengsfeld event that they have a great deal of experience in modular GTGs.

So, what to do?

I think I'll sleep on it.

Regards,  IanT

[Kalinowski]

On the subject of transition curves, I have built a 30 foot length section at one end of my circuit to overcome problems at "Rumble Corner" so named because Geoff's Crab kept flying off at speed into the leaf bin, upsetting the cat and the frogs, not to mention bending the buffer beam on the Crab somewhat.

The radius is 13 feet which is just about right for a six coupled loco at speed with flanges on all driving wheels. I used varying thicknesses of longitudinal tapered wood section supporting the wooden sleepers under each 3 foot section. If you have plastic track then the same technique can be used, providing there is a gentle lead in to the curve section rising to maximum elevation and a then corresponding gentle lead out to flat and level.

Works a treat and well worth the trouble, also it looks good as the locos "lean in" realistically to the curves.

regs PK

[IanT]

Interesting radius (13') you've used there Peter,

The NEM 113 'Easement' recommendation I refered to below states that "Easements are especially useful on tight curves, whilst they may be ommitted on curves > 60 x G"

So as a 'NEM Rule of Thumb' (in G3 terms) this suggests that in practice, curves above a radius of 3.81 metres (12.5') shouldn't require transitioning. Of course that may not be the same thing as saying it will look right.

For curves under the 60G radius they give various way of calculating the 'easement' but I think I kind of prefer their bent stick - sorry - "Elastic Staff" method best. It seems wonderfully understandable somehow, but I'm sure Cabbage will prefer a more technical/mathmatical approach.   

[cabbage]

IanT,

The superelevation at differing radii and the formulae to work out transitional curves has already been written up by me for the Technical Manual. All you have to do is follow your finger along the printout...

quote:
"If you can't show the maths then its an "opinion", and not a fact"
unquote:

My late father always had a low opinion of "opinions"...

regards

ralph

[Ted Sadler]

A magnificent Dutch modular HO layout (usually seen at the Chatham Dockyard railway show) comes to mind. The individual scenic modules are not all directly connected, but are separated by short(ish) hidden sections. Using this technique, the individual modules can be designed with some latitude.

Why not, therefore, have somewhat flexible connecting sections available for use at 'multi-modular' shows and get-togethers? A lightweight base that opens out like a fan and locks into position, onto which track is laid in situ would suffice for the odd corners that just won't match up otherwise. At worst, a length of track might need to be cut to suitable length at each event, but that's not so expensive given the benefits.

Just a thought. Ted