Separation between ground and viaduct tracks

[wonton]

Hello everyone!

 

After more than 20 years I'm trying to retake this hobbie building a japanese layout, but I'm too newbie and I have a lot of doubts. I cannot find the answer to one of my doubts so I'm trying here:

 

If I have a half circle of KATO 20-132 ground curves (45º 348mm) could I place right next to it a half circle of KATO 20-520 viaduct curves (45º 315mm) or should I make the separation between tracks longer using KATO 20-510 (45º 282mm)? I would prefer to have the ground tracks and the viaduct tracks as close as posible but I'm not sure of what separation should they have.

 

Thank you very much and kind regards!

[railsquid]

You should be fine with the 348mm/315mm combination, assuming you're using the high-level (55mm) Kato supports.

[wonton]

Thank you railsquid!

 

Then, assuming that I have these 348mm/315mm combination, if the KATO 20-520 viaduct curves enter into the viaduct station (KATO 23-125), could it be a separation problem with the outer ground tracks? Looking at the viaduct station segments it seems that the track is very very close to the station lateral, but I'm not sure if the station could occupy the outer tracks space...

[railsquid]

Not quite sure if I follow you. The outer, ground-level track should run on the ground immediately adjacent to the station? Could work but I don't have one of those so am not entirely sure. Can you post a diagram of what you want to do?

 

(I'm doing some pretty hairy stuff with Kato track at the moment so am happy to help if I can. However my high-level stuff is Tomix as it seems somewhat more compact and flexible than the Kato versions, though interfacing the two levels will be a tricky problem).

[wonton]

Hello railsquid!

 

I've attached an image to explain this:

 

- Gray tracks are the ground level. These curves are KATO 20-132 (45º 348mm)

- Green tracks are the viaducts from the ground level to the upper level. These curves are KATO 20-520 (45º 315mm).

- Brown tracks are the upper level.

- The red rectangle is the KATO 23-125 viaduct station.

 

My doubt is if there could be any problem with the separation between the gray tracks and the green tracks + viaduct station.

 

I was thinking to use Tomix tracks with Kato stations but I was having a lot of problems adjusting the design so I'm trying again using Kato tracks.

 

Since I don't have too much space (150cmx75cm) I would like to have gray and green tracks as close as posible so my curves aren't too tight.

 

[railsquid]

I'm pretty sure it will be OK. I can't test it however.

 

BTW the curves should definitely be fine, I was testing something similar earlier and if you've got the standard distance between tracks there will be no problem. I've got one place where one of the support columns of a raised section is right next to the outside of a 315mm curve and there's enough clearance for a Shinkansen car.

[wonton]

Perfect! Thank you very much! It helped me a lot!

[inobu]

I don't think your problem lies in the track separation but more so in the grade. 

 

The transition onto the second level is critical in that resistance builds up on the motor car as it pushes and pulls the train through the curve. The piers must be placed

so it provides an acceptable grade into the curve. The concept is like pulling an extension cord around two corner walls. The corners start to bind the cord making it harder

for you to pull the cord through. The tighter the curve the greater the resistance. 

 

If I remember correctly I had to get the second pier set.  Kato N 23016 Unitrack Gradual Incline Pier Set

This piers set allows you to manage the grade by increasing the variety of pier heights.

 

 

The other problem is that some of the longer cars will clip the walls on the single viaducts track if you placed the grade on the curve. I had to bend the walls out a little on some of the tracks when they were already at grade.

 

Inobu

Edited September 9, 2014 by inobu

[katoftw]

Also if you plan on using catenaries, the bases will impact the space next to the viaducts.

 

Also a note on your green tracks, you need 6 sections of track to raise up to the 50mm height.  Each peir incline section goes up 5mm, 15, 25, 35, 45 until 50.

[wonton]

Hello everyone!

 

Just before read your last posts I realized that my problem would be the grades. Just because of that I've remade my track design to gain more distance in the green tracks. I attached my new design.

 

I would like to ask a very specific question, I hope some of you know the answer:

 

With my new design my viaduct curves have 103.2 cm, this is a 4.8% grade. Also, the curves are R=249mm 45º.

I'm planning to have this trains:

Tomix 92418 - Narita express (3 cars).

Tomix 92286 - Shinkansen Tokaido (4 cars).

Tomix 92260 - Yamanote line (3 cars).

 

Do you know if this curves and their grades could be a problem for these trains?

 

Unfortunatelly I don't have too much space for my layout :-(.

 

Thank you very much and kind regards.

[kvp]

The absolute minimum for Tomix shinkansen is R280, but if you want to use viaduct tracks, then you will have to go much higer, since otherwise the cars will hit the sidewalls. Also, the highest grade that is usable is 4%, but only if you run sets that are no longer than 4 cars. For close coupled sets, like many shinkansen and some emu-s, you have to use a 1-2% transition grade, both at the bottom and the top of the slope. A general rule is that on curves, these values have to be halved, so 2% max grade with 1% transition sections.

 

In your case, i would go with two levels, one separate high level loop for the shinkansen and one or two ground level loops for the yamanote/nex. You might be able to get away with R280 curves for the shinkansen, if you use normal tracks without side walls and build your own elevated stucture, since the cars will be able to hang into the curves as much as they want. The same is true for the nose sections, that will hang out, so you should make sure, the on the ground level, the front of each train clears any support structures that might be in their way. If not, then you have to move the support colums inside both loops or use an upside down L shaped or a T shaped support structure. Going above R280 would sove some of the problems, but for vertical transition, you will need lots of a space. The same is true if you wan to use viduct tracks with sidewalls, because the longer shinkansen cars need a lot of space. For turnouts, the Tomix R280 turnouts are the smallest that will work, but the bigger the better.

 

ps: Accidentially for the Tomix shinkansen you mentioned, i know that the set starts to look correct above R400.

Edited September 10, 2014 by kvp

[railsquid]

Hello everyone!

 

Just before read your last posts I realized that my problem would be the grades. Just because of that I've remade my track design to gain more distance in the green tracks. I attached my new design.

 

I would like to ask a very specific question, I hope some of you know the answer:

 

With my new design my viaduct curves have 103.2 cm, this is a 4.8% grade. Also, the curves are R=249mm 45º.

I'm planning to have this trains:

Tomix 92418 - Narita express (3 cars).

Tomix 92286 - Shinkansen Tokaido (4 cars).

Tomix 92260 - Yamanote line (3 cars).

 

Do you know if this curves and their grades could be a problem for these trains?

 

You certainly won't get Shinkansen cars around the 249mm curves. They just about squeeze through the 348mm viaduct sections.

[wonton]

Ufff, bad news :-(. Thank you for your detailed answer, I will study it.

 

Your suggestion of having 2 separate levels is very interesting but with my space (150x75) I'm not sure I can do interesting things in the ground level.

 

I think my best option is to have a bigger table, but it will be very difficult, I will have to negotiate it with my wife ;-).

[railsquid]

I've got somewhat more space (180 x 90 + some extra bits) and though I'm planning a high-level Shinkansen track, it won't be a loop; I'm connecting it to the ground-level loop via a gradient partially on a curve (381mm radius), which is realistically the most I can do and still use the ground level space effectively.

[katoftw]

viaduct take up alot of space.  with the space you are working with, do away with the viaducts.

 

also plan 2 still doesn't have enough pieces to rise to 50mm.

[railsquid]

It's the viaduct gradient between levels which takes the space, once you've got the track up there it give you more options in some ways.

 

But yes, that's definitely too small a space to be working with loops and multiple gradients, especially with Shinkansen.

 

Maybe, just maybe a figure-of-8 loop with the Shinkansen station in the centre and 348mm curves might just work.

[macdon]

As merely a suggestion, I would go via kvp's idea of doing 2 separate levels so you can eliminate any problems with gradients. Besides, shinkansens do run in their own world so to speak.

For trains hitting the tighter viaduct walls - one option is to go via diy. Get plywood that is same size with your table, lay down your shinkansen tracks and mark the inside and outside cutting line with ample space between edge and tracks. For viaduct walls, thin plastic, sintra, styrene strips could be glued around then spray painted grey for concrete. I bet it would even run quieter compared to plastic viaducts.

For viaduct piers, you can still go via diy or buy kato/tomix piers.

 

Having the shinkansen up will leave you to design the ground level with a more open/cleaner slate - maybe a commuter line or like kvp suggested, even 2. Even if your ground level tracks have portions that may go under the viaduct tracks - you can elect various pier designs like a "T", upside down "U" or any pier and beam combination. If you went for a plywood floor viaduct, you even have a bit of freedom from pier placement - and not necessarily under each track section.

 

Your structure and scenery will dictate your excitement for the ground level and you might also consider a tram or moving bus line as they both take tight curves. Japanese rail have so much to offer and one good consideration is to 'future proof' your layout.

 

Mardon

[inobu]

The solution may lie in the dynamic of the layout. Use terrain to elevate one stations and viaduct the other. Although both stations are on the same plane the perception is two levels.

 

Remember your layout is a stage. You use props to control the viewers perception.

 

 

Inobu

[wonton]

Thank you very much for all of your suggestions!! I really appreciate them.

 

The problem is that I'm not too skillful with diy ;-), so I would prefere to work with items already built. Anyway, or I get a bigger table or I have to do myself some things.

I like more and more the idea of have two separate layouts but I imagine the viaducts would have to be the outer circle and as I said in a previous post I don't know if the space will be large enough for an interesting ground design. Any idea or what could I have in the ground level? I will take a look to the "Inspirational Layouts" and "Personal layouts & projects" forums but I don't know if it would be easy to find any layout for my dimensions.

 

I like the idea of elevate the second station so they are at the same level, but I'm not sure I can build that by myself.

Edited September 11, 2014 by wonton

[katoftw]

also shinkansen wont do any smaller the R348 viaduct curves.

[wonton]

Finally I'll try to get more space, maybe 200x100.

 

Anyway, one question: do you know any example of a multilevel station? I really like kvp's idea of having a viaduct level separated of my ground level, and I would like that the viaduct station was one of my ground level station, but I have no idea of how could I make this, maybe some kind of mixing KATO viaduct station (KATO 23-230) with for example KATO overhead station (KATO 23-122)?

[wonton]

Hello again.

I keep thinking in the idea of having two separate circles, one elevated for the shinkansen and one ground level. Since I have too little space I was thinking in having a little part of the ground level under a section of the elevated level. But then I'd have to use an inverted U pier instead of the T pier and I guess I should do it by myself. Do you know any "easy" way to build this kind of pier so I can have a track under the viaduct?

Edited September 15, 2014 by wonton

[macdon]

Both kato and tomix have piers for both single and double track viaducts but I think only tomix sells crossbeams to connect to their single viaduct piers to form an upside down "U" shape.

 

I have a similar case in my layout but I used 2 kato piers with fiberglass sheet to serve as beam.

 

 

Mardon

[wonton]

I like the idea of piers with fiberglass sheet, macdon. Do you think it could be use in the connection between one of the kato viaduct station segment and the viaduct tracks?

If this is not possible, I see this pier is used to make this connection.

Could it be customized, for example, cutting the lateral bar, so a track pass under it? I think is not possible because it seem to low, but I would like to be sure.

[kvp]

The height seems to be good (just a bit lower than the Tomix version that is designed to allow trains under it), but i don't know if the supports would remain stable enough when you remove the horizontal bars.