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Turn radii

699 Views 7 Replies 6 Participants Last post by  hazelbrooks55
Hi all, complete newbie here. I am receiving some base boards tomorrow to get me started and it is my plan to run Southern Electric 3rd rail trains, sorry but that`s my thing. I don`t have a great deal of space but I would like to have a continuous run two track circuit as the main feature. My question is, assuming Peco flexi track, what is the absolute minimum radius you can get from this track? Any advice appreciated.
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Hello and welcome. Honestly do not know the answer to your question. By quick search, I found this.
Hope this will be helpful
Thanks for that, looks like I will have to make some boards for turning at each end of my track.
Good practice is to not have anything less than Radius 2 which for OO gauge is 438mm.
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A better question might be what is the minimum radius that the rolling stock you want to use will cope with.
Best practise is to use the largest radius your space will allow. (The absolute minimum radius for BR(SR) standard mk1 based third rail EMU's was four chains, which scales 1056mm/41.5" radius in OO; and this required the coupling and gangway systems to be specially adjusted to allow the train to creak, groan and squeak its way in and out of Southampton, on the Northam curve.)

As mentioned above RTR OO models are now made with R2 capability, 438mm radius. Longer vehicles like coaches, look better on curves as the radius increases.

The 'traditional' advice is that if a radius under 24" is required, then use set track. (In OO set track the largest radius offered is 572mm/21.5" '(R4) and this is only available in code 100 rail). However, that advice dates from the days of code 100 rail as 'standard'. Code 75 flexitrack is way easier to bend into smooth curves, and will go tighter without difficulty, I have managed scale for 1 chain - just over 10" - but strictly only for wagons in locations like docks, where a horse or road vehicle was used to move the wagons.
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As you want 2 circuits then the outer one will have to be R3 = 505mm that is to the centre line and thus you can add 10mm for the rest of the track and about the same for coach end overhang depending upon how long the coaches are so you need a board = 2 x (505+10+10) = 1050 as you may already found out by now.
Thank you all for your kind advice, the more I think about this the more I am leaning towards an end to end layout as lack of space means that to achieve constant running I would have to build a layout beyond my financial means. Oh dear, decisions decisions.............
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