Figure 8 layout

Longvallon

Longvallon

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Hello,
I'm planning to build a figure 8 layout. I have two plans (see below). What's the best solution ? All your advices are welcome. Thanks.

PLAN A.jpg

PLAN B.jpg
 
The bridge will only work if you can gain enough height, you need to ensure the gradient is not too steep for you trains. Both plans will need isolating sections if you are using track power.
 
Thanks. In the bridge version, the gradient will be 5%.
I forgot a few things.
-Curves radius: 600mm (Piko R1)
-Layout dimensions: 1.40 x 2.60 m
 
If you have followed this forum for a while you will know that there is nothing wrong with using R1 curves - my indoor layout is all R1 curves and points - as long as you know you will be limited to the locos and wagons you can use. Even more so if you go for the flyover option. I think I would go for the flat layout / level crossing if this is you first layout, if you definitely want a figure of 8. You could have one or two sidings then. Definitely not recommended to have points on curved gradients.

I see you have limited space but unless this is more garden than railway and you just want to watch a train running through your landscape I would go for an oval with passing loop. Then you could have two short trains for a bit of variety.
 
If you want an '8', I would most definitely go with the diamond crossing. The slope you need to clear a flyover is steep and the twisting on such a sharp curve may result in poor running and derailments. It is not impossible, certainly, but it might give you nothing but frustration in the future. As said above, pointwork on such a grade and twist will be awkward.
Do consider a simple circuit with a siding or loop - It may well look more prototypical and run better - and two trains and/or shunting.
 
hello,
you should lay out a test-layout. 140 is very small for R1. the manufacturers measure their circles/curves from middle between rails to middle between rails. (for the 260 for the "8" the same aplies)
do you have space for 150 x 290? if yes, use it!

for the bridge...
for that idea you need every piece of curved track to gain 2.5 cm, the two straights on and under the bridge stay horizontal.
that is doable, but restricts you to somewhat shortish trains.

both of your plans do not need any isolations or other gizzmos.
 
Longvallon said:
Thanks. In the bridge version, the gradient will be 5%.
I forgot a few things.
-Curves radius: 600mm (Piko R1)
-Layout dimensions: 1.40 x 2.60 m
Click to expand...

I doubt you will get 5% (1 in 20) in the bridge version because you need vertical transition from the flat under the bridge leading into the grade and do the same at the top of the hill going over the bridge so your grade length will be much shorter than the crossover distance. I'm not sure what loco and rolling stock you have but a Stainz for instance will need at very minimum 190mm or 7-1/2" height difference including the the track height. Even at that, it will barely make it under the bridge. So if your grade length is say about 9 curve lengths of approximately 314mm being 2826mm, it would be 2826 / 190 = 6.72% or 1 in 14.87 aprox. That grade is very steep! You will also ideally need to bend the 4 transition tracks to vertical curves so the transition to and from grade is gradual. This may not exactly be the same as your situation or how you would go about it but that's what the numbers say for the scenario I have speculated. :think:
Edit: Hmm, the transitions tracks will actually make the grade height calculation less than I specified but that will give some clearance. It's tricky to work out exactly but probably more like 6% or 1 in 16.66 with no clearance.

The R1 figure 8 flyover has been thought of before but it is really pushing the limits. Your train will struggle up the incline then race down the other side like a roller coaster possibly wearing the engine out prematurely. It won't present anything that looks prototypical.
 
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Think the bridge version would be more interesting but I doubt you can get enough height and less grade with R1 curves. Steep inclines and tight curves don't mix. If you go with the crossing you could later place switches at either end making a larger loop and maybe a little more interesting, Bill
 
Agree fully with all of the above.... with R1 track the bridge version just won't work due to the excessive gradients involved - even if you could get a small loco to climb it, it wouldn't be able to manage more than one piece of rolling stock.....
Stick with the crossover version - it will be much more fun and less hassle, and your trains will actually work! As already noted, no special wiring or insulators will be needed because the crossover already has the required insulation built in.

Jon.
 
Here's a figure of 8 with two (admittedly short) sidings which allow end-to-end and round-and-round running. I'm afraid I've used Imperial measurements but if my sums are right the layout takes up approx 2.6m x 1.5mIMG_20180623_0001.jpg
 
Zerogee said:
Agree fully with all of the above.... with R1 track the bridge version just won't work due to the excessive gradients involved - even if you could get a small loco to climb it, it wouldn't be able to manage more than one piece of rolling stock.....
Stick with the crossover version - it will be much more fun and less hassle, and your trains will actually work! As already noted, no special wiring or insulators will be needed because the crossover already has the required insulation built in.

Jon.
Click to expand...
Agree
 
Longvallon said:
Thanks. In the bridge version, the gradient will be 5%.
I forgot a few things.
-Curves radius: 600mm (Piko R1)
-Layout dimensions: 1.40 x 2.60 m
Click to expand...

Are you able to use a space just a little bit larger? You may then be able to make the figure 8 with flyover track have a more gentle grade or you could do something like below with a junction which is at mid level.
The junction could be used to have 2 different circuits where you could isolate a 2nd train or hook the points together so they alternate the rout then it would function similar to a figure 8.

PseudoFigure8_00.jpg

PseudoFigure8_00.jpg

  • Media owner Paradise
  • Date added
The junction is at mid height. Rigged points could operate layout as a pseudo figure 8
 
playmofire said:
Here's a figure of 8 with two (admittedly short) sidings which allow end-to-end and round-and-round running. I'm afraid I've used Imperial measurements but if my sums are right the layout takes up approx 2.6m x 1.5mView attachment 239531
Click to expand...
You have created two short circuits in that. Might work for Playmobil on batteries but not for track power (unless you start using complicated stuff).
 
:wasntme: They look like sidings if you open up the larger image so would be just like a plain 8
 
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Just out of curiosity I made a few plans to explore a minimum figure 8 flyover using R1 600mm radius curves. The under and over sections of track are straight to permit vertical transition bending of the rail. The curves are all at the same continuous grade.
The bottom design has horizontal transition curves (Piko 124.3mm radius) from the straights which look a lot nicer and make each grade that little bit longer.
A Stainz locomotive for example is 190mm high including track. Using the bottom design and keeping clearance to an absolute minimum a near 5% or 1:20 grade should be achievable.

Minimum Figure 8 Flyover_00.jpg

Minimum Figure 8 Flyover_00.jpg

  • Media owner Paradise
  • Date added
 
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Paradise said:
Just out of curiosity I made a few plans to explore a minimum figure 8 flyover using R1 600mm radius curves. The under and over sections of track are straight to permit vertical transition bending of the rail. The curves are all at the same continuous grade.
The bottom design has horizontal transition curves (Piko 124.3mm radius) from the straights which look a lot nicer and make each grade that little bit longer.
A Stainz locomotive for example is 190mm high including track. Using the bottom design and keeping clearance to an absolute minimum a near 5% or 1:20 grade should be achievable.

Minimum Figure 8 Flyover_00.jpg

Minimum Figure 8 Flyover_00.jpg

  • Media owner Paradise
  • Date added
Click to expand...

Oops, iit seems the photo is not available to view.
 
Many thanks for all your advices. The diamond crossing is the best solution. I need some money but my Personal Prime Minister doesn't seem really happy with my project...Maybe a few flowers will do the trick ?
 
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