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Offline Johnvr  
#1 Posted : 24 October 2019 21:41:42(UTC)
Johnvr

South Africa   
Joined: 03/10/2010(UTC)
Posts: 1,149
Location: Cape Town, South Africa
Hi all,

I have been comparing notes between C-Track geometry and K-Track geometry, and wondering why there are some geometric differences between them.

The C-Track standard curve point is 24.3° and the K-Track standard curve point is 22.5°. Why are they different ?
The C-Track standard length is 360mm (188mm + 172mm) and the K-Track equivalent lengths are 324.9mm (168.9mm + 156mm). Why ?
The C-Track spacing between tracks is 77.4mm and the K-Track standard spacing between tracks is 64.6mm Why ?

Both of these C-Track and K-Track forms have complications, and there are numerous articles on how to construct different layouts where the tracks fit together. Some of these are really interesting shapes, but go to a lot of trouble to make things fit. Those 5.7° C-Track curves are difficult to work with and you only get them in R2.

I think that C-Track got the distance 360mm right but the angle wrong, and K-Track got the angle 22.5° right but the distance wrong.
I believe that a best-in-class track would combine the best features of both of these.

In my theoretical world,
1) the standard curve point should be 22.5°. Because 2 x 22.5° = 45°, and 4 x 22.5° = 90°. All angles become easy to join, whether you are doing reverse loops or X-crosses or anything.
2) The standard length of 2 tracks should be 360mm. Because this fits nicely with the R1 radius curve and allows for subsequent concentric circles. We need to eliminate the small straight sections required in the K-Track range to make up the 360mm.

Combining the best of these C-Track and K-Track features, I believe that the optimal spacing between tracks is calculated to be 71.61mm.
(see calculations below)

A track line spacing of 71.61mm will allow the perfect match incorporating 22.5° points and 360mm combined straight sections.
All crossings will be completely seamless and will fit snugly into the track geometry.
All points will be able to curve at 22.5° and curve up to 45° with no problems, or curve back to parallel tracks, go to reverse loops, etc.

In C-Track terms,
instead of the 24188, we would have a 24184, and instead of a 24172 we would have a 24176, and instead of a 24077 we would have a 24071.
In K-Track,
it would not be necessary to have all of those small sections like 2204 and 2208, etc to get back to the 360mm.

Using a little trigonometry, one can calculate these angles and distances using SINE and COSINE functions.
It's just something that I have been thinking about for a while BigGrin
And having a bit of fun with maths !

Slide1.JPG

Slide2.JPG


Regards
John
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Offline Minok  
#2 Posted : 24 October 2019 22:14:20(UTC)
Minok

United States   
Joined: 15/10/2006(UTC)
Posts: 2,076
Location: Washington, Pacific Northwest
Glad I'm not the only one nerding about about model rail maths and engineering.

I'd thought the angle of the turnout on C-Track, ties to the fact that its an R1 curve, but one could end the turn-out portion when it gets to the angle you think is ideal.

I do agree the rigid track bits (as I create my C-track layout) often results, when one is fitting as well as possible to a room geometry, in connecting A->B by a bizarre mix of odd pieces to accommodate an offset of a few mm and degrees.
Toys of tin and wood rule!
---
My Layout Thread on marklin-users.net: InterCity 1-3-4
My YouTube Channel: https://www.youtube.com/user/Minok1217/
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Offline kiwiAlan  
#3 Posted : 24 October 2019 22:14:37(UTC)
kiwiAlan

United Kingdom   
Joined: 23/07/2014(UTC)
Posts: 4,603
Location: ENGLAND, Didcot
Originally Posted by: Johnvr Go to Quoted Post

The C-Track standard length is 360mm (188mm + 172mm) and the K-Track equivalent lengths are 324.9mm (168.9mm + 156mm). Why ?


I think you are wrong on your K track spec. The 2200 track is 180mm which is the same as M track and the average of the two C track straights. The two K track lengths you list are for matching the effective straight lengths of curves, the same way the C track ones do.

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Offline H0  
#4 Posted : 25 October 2019 08:39:25(UTC)
H0


Joined: 16/02/2004(UTC)
Posts: 13,533
Location: DE-NW
Hi!
Originally Posted by: Johnvr Go to Quoted Post
The C-Track spacing between tracks is 77.4mm and the K-Track standard spacing between tracks is 64.6mm Why?
To make things complicated C track also has a spacing of around 64 mm while K track also has a spacing of around 55 mm.
AIUI the R2 turnouts of C track aim at the M track dimensions.

In an ideal world we would see an ideal geometry shared by M track, K track, and C track.
Regards
Tom
---
"In all of the gauges, we particularly emphasize a high level of quality, the best possible fidelity to the prototype, and absolute precision. You will see that in all of our products." (from Märklin New Items Brochure 2015, page 1) ROFLBTCUTS
UserPostedImage
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Offline hxmiesa  
#5 Posted : 25 October 2019 10:02:44(UTC)
hxmiesa

Spain   
Joined: 15/12/2005(UTC)
Posts: 2,744
Location: Spain
I use K-track "slim" geometry, and it is absolutly wonderful to work with!
Slim point angle is around 15º, and parrallel distance is around 55mm. (Prototype would be around 52mm distance, so very close!)
The flex-track allows for all kinds of realistic lines, and the existence of the slim DKW allows for most design options.
With K-track, it is possible to fit a lot of slim DKWs and points into very lillte space, compared to the incredibly bulky "slim" C-track design.

I understand that the standard R2 C-geometry is basically mimicking the M-track geometry. It´s truly a toy-like geometry, with origins back to the beginnings of the H0 scale, around the years of WW2. Angry

I too, dont understand the reasons for the K-track R2 geometry. It´s also toy-like, but the track pieces doesnt allow very well for teppich-bahning, and also breaks too easy. Not suitable as a toy at all!

In short; Märklin really nailed it with the slim K-track geometry, but for some reason most people here dont seem to get it?! lol
Best regards
Henrik Hoexbroe ("The Dane In Spain")
http://hoexbroe.tripod.com
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Offline RayF  
#6 Posted : 25 October 2019 13:43:02(UTC)
RayF

Gibraltar   
Joined: 14/03/2005(UTC)
Posts: 15,461
Location: Gibraltar, Europe
It is what it is!

In my opinion there is not much point in suggesting a different track geometry at this stage, unless there is a possibility in the near future of a new type of track being produced, which I very much doubt.

When I moved from M track to C track I initially tried to keep the same track layout, but soon realised that the geometry made it very difficult. I believe you have to look at one type of track system, explore the possibilities of that system, and then tailor your track plan to the geometry of that system.

Ray
Mostly Marklin.Selection of different eras and European railways
Small C track layout, control by MS2, 100+ trains but run 4-5 at a time.
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Offline mbarreto  
#7 Posted : 25 October 2019 13:55:15(UTC)
mbarreto

Portugal   
Joined: 18/02/2008(UTC)
Posts: 858

C track geometry tries to follow M track geometry but with the constraints of the rigid wider ballast. I think that is why there angle and length differences.

C and k it is what we have to live with and I don't think it will change soon.

C track has what for me is the most impressive track coupling between 2 pieces of track.
I also prefer by far the geometry of K track, but that is indeed more professional than hobby style track like C track.

Mostly Märklin H0.


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Offline clapcott  
#8 Posted : 26 October 2019 22:01:00(UTC)
clapcott

New Zealand   
Joined: 12/12/2005(UTC)
Posts: 2,250
Location: Wellington, New_Zealand
Originally Posted by: RayF Go to Quoted Post
It is what it is!


I Concur,

While I, too, enjoy a bit of mental gymnastics on occasions - reality is a persistent hangman.

In this discussion so far there is no mention of the related specification requirements to ..
- support (legacy) train stock
- - flange size (rail height) - as it affects traction
- - flange gauge spacing - as it affects guide rails
- frog tolerances -
- - for "acceptable" gap for smooth transit (visual audible)
- - power resilience - (consider T-Track 2 rail from the same mould )
- high speed to standard geometry "modelling" ease 12.1 * 2 = 24.3






Peter
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Offline Goofy  
#9 Posted : 31 October 2019 14:58:29(UTC)
Goofy


Joined: 12/08/2006(UTC)
Posts: 8,072
C-tracks replacement M-tracks.
Even M-tracks does not show same geometry like K-tracks.
DCC means Digital Command Control.

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Offline michelvr  
#10 Posted : 31 October 2019 15:22:54(UTC)
michelvr

Canada   
Joined: 06/07/2012(UTC)
Posts: 1,040
From my perspective it is the best that Märklin provides to run our trains on! Either Märklin C or K track will work for you and you'll be happy. I've done both K and C track and right now I’m almost finished with my track laying on this layout. Using Märklin’s C track this time and adding some features like superelevation on the curves and creating access holes for the turnout motors makes it better.

Discussions on this is a healthy approach in learning what is really actually missing but knowing the limitations help in planning.

If I was to do everything over I think at today's prices I would look into a different hobby! Why? Yesterday I replaced some right turnouts for lefts and the new prices are a SHOCKER at $41.50, too much for my taste! Luckily I have what I need and I’m done with building. Hey it is what it is but when fun stops at these prices it's going to kill this hobby!

My two cents!!!!!!
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Offline hxmiesa  
#11 Posted : 31 October 2019 16:37:52(UTC)
hxmiesa

Spain   
Joined: 15/12/2005(UTC)
Posts: 2,744
Location: Spain
Originally Posted by: clapcott Go to Quoted Post

In this discussion so far there is no mention of the related specification requirements to ..
- support (legacy) train stock
- - flange size (rail height) - as it affects traction
- - flange gauge spacing - as it affects guide rails
- frog tolerances -
- - for "acceptable" gap for smooth transit (visual audible)
- - power resilience - (consider T-Track 2 rail from the same mould )
- high speed to standard geometry "modelling" ease 12.1 * 2 = 24.3

Interessting subjects, and it would have been nice to have your own views on that too...,

Obviously the high rails of the K-track reflects the legacy support of ancient M-track. (huge wheel flanges)
On both M-tracks and K-track R2 switches it is clearly seen that the track contact is based on using the flange of the wheels, rather than the wheel rolling on the track. (EVEN if the track is so high (Code 110))
At least on the slim K-tracks switches the frogs are not inlayed with a metal strip, and relies on the actual rail to maintain contact.

I dont remember how that is with C-tracks (I dont own any), and I cant look it up right now.
However, with the lower code of the rail, and the lesser need (if any?) to change DC geometry wheels to AC geometry wheels, the meassurements and tolerances must be much narrower for C-track.
M- and K-track allows for huge gaps and very roughly laid track, which works well with AC wheels. (But not at all with DC wheels)

I re-gauge all my wheel-sets to 13,9mm -as per jvuye´s suggestion, which work well even for DC wheels.

IMHO no advantage (or "modelling ease") between high speed and standard geometry in C-track. The 12.1º angle has no advantage relative to the grid. Totally inferior to the K-tracks 14,3º (15º) slim angle. However the real BIG problem of slim K-track geometry is how the 71mm supplement rail piece is integrated. (=how the points miss a detachable 12.1º piece of roadbed at each end and on each side...)

Finally I would like to comment the "power resiliance" subject that you mention;
Many people consider the T and C-track almost identical, except for the pukos. IMHO no so!!!
C track has 4 connection points for the 2 conductors; 2 for the outer rails and 2 for the pukos. You can then cut a couple of metal strips for the outer rails and make your own contact-tracks, leaving 1 connector for each rail.
T track only has 2 connectors. 1 for each rail. -The 2 rails are already separated from the factory (of course...) You have no redundant connectors for elevated conducting safety.
Best regards
Henrik Hoexbroe ("The Dane In Spain")
http://hoexbroe.tripod.com
Offline applor  
#12 Posted : 01 November 2019 00:46:11(UTC)
applor

Australia   
Joined: 21/05/2004(UTC)
Posts: 1,402
Location: Brisbane, Queensland
K track slim parallel distance is 57mm. As for 'optimal' parallel spacing, it really should be NEM of 52mm as mentioned.
Unfortunately K track has no wide radius curved points, so that is a let down. I don't use K track R2 (C track R1) 360mm so that rules those out.
The good thing about K track is you can cut it and fit joiners at any length of track (just like the 2 rail guys) and so you can create any length curve to fit.
The down side is the high rail profile.

By modifying the ballast profile on the C track wide radius points you can create a more realistic parallel track distance.
If you're doing that for better realism you'd be doing additional hand ballasting on the C track to hide the cutting anyways.
I do like how the C track turnout geometry lets you fit them in any combination and maintain the right lengths/angles.
modelling 1954 Germany (era IIIa)
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Offline David Dewar  
#13 Posted : 01 November 2019 12:44:19(UTC)
David Dewar

Scotland   
Joined: 01/02/2004(UTC)
Posts: 6,762
Location: Scotland
I only use C track and the layout is built with that and have no intention of adding K or any other type track. Regards geometry I was useless at school and never understood it anyway lol.
A good use of C track can be seen on Rays layout which looks really good.
Take care I like Marklin and will defend the worlds greatest model rail manufacturer.
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Offline hxmiesa  
#14 Posted : 04 November 2019 12:00:17(UTC)
hxmiesa

Spain   
Joined: 15/12/2005(UTC)
Posts: 2,744
Location: Spain
Originally Posted by: applor Go to Quoted Post
I don't use K track R2 (C track R1) 360mm so that rules those out.

No, K-track R1 is the same as C-track R1, and M-track R1. (360mm)
K-track R2 points use 22,5º angle. (3/4). Its R2 is slightly smaller (around 13mm less) than M and K-track R2.
It also has an "industrial" radius like M-track, which we can then call R0.
Best regards
Henrik Hoexbroe ("The Dane In Spain")
http://hoexbroe.tripod.com
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