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Minimum HO radius

Posted: Thu Aug 17, 2017 12:16 pm
by Albert
OK, I know this will go against the grain for most of you, but I want to put together a very small layout with absolutely no landscaping and no consideration for realism.

Having got that out of the way, I'll explain.

My main interest in model trains is the stuff below the track head, particularly the electrics and electronics. My current HO/OO 'layout' consists of a 2 ft square of ply with a 22" diameter circle of flexi that I'm using to experiment with various sensors and to learn how to control DC with an Arduino. Cobbling that together with smooth enough joints wasn't easy, although I recognize that my technique could do with improvement. In the near future I want to include things like points and decouplers, so I'll need to start again with a different arrangement with room for straights. To make all this easier to re-arrange I'd like to go over to settrack with tight 30 degree curves

I only run old two axle locos with one or two short 4-wheeler wagons so tight curves should not be a problem.

Ideally, I don't want to go for anything much bigger because I need to just tuck it behind the sofa and then plonk it on the dining room table for use. 2'x3' is about the biggest I'd prefer but then I still run up against the need for tight curves.

Depending on where I look HO 1st radius seems to be either 360mm or 370mm, but I seem to recollect seeing something listed at around the 250mm mark.

Any suggestions for sources of suitable track? I have a feeling that Bufferstop could probably point me towards something, but all ideas are welcome.

Re: Minimum HO radius

Posted: Thu Aug 17, 2017 1:17 pm
by b308
Playcraft used to do some around the 12" radius mark but they are long out of production. I don't know of any others. 250mm (just under 10 inch) radius is very tight for 16.5mm gauge and I doubt if anyone would bother to produce such track, even in N/009 it's tight!

Emmetman will tell you how to bend flexitrack to that radius, I've no doubt, as many of his layouts feature such radii!

Re: Minimum HO radius

Posted: Thu Aug 17, 2017 3:14 pm
by Bigmet
Lima also at one time offered spectacularly small radius OO set track. When I am next home I'll take a look at the small quantity I have recently acquired unintentionally in a 'mixed lot'. Unfortunately, most such products will be in plated steel rail, and this is very vulnerable to corrosion if it has not had real care over the years since production.

Re: Minimum HO radius

Posted: Thu Aug 17, 2017 3:58 pm
by Beynac
You can use 250mm radius.

Re: Minimum HO radius

Posted: Thu Aug 17, 2017 5:29 pm
by Albert
Thanks, all. Looks like I might have to up my maximum baseboard size a wee bit.

I'm sure that with a bit of advice from the experts I'd be able to do a better job of flexi-track laying, but I'd prefer to have an easier way to change the layout to accommodate different track arrangements.

Re: Minimum HO radius

Posted: Thu Aug 17, 2017 5:30 pm
by Bufferstop
You could use flexi with a technique I used for an "around the Christmas tree model. I started with a circular piece of ply around 250mm radius. It had a 5mm hole at the centre used when cutting it out. I made a rotating cutter by drilling a 5mm hole in a 15mm wide lath. I then made a notch in which to rest my knife blade at 250mm radius. I then used the cutter to create a 500mm disk. then I made another notch 15mm in and cut a second circle leaving just enough uncut to stop the centre falling out. I did the same again only this time the notch moved in by the width of the sleepers. Finally I cut a further circle this time by hand drawing a small circle at the centre which would make a hole big enough for the tree trunk.
I spread the ply and the underside of the card with PVA except for the ring and the hole at the centre. Pressed them together using the blunt end of the 5mm drill as a guide, put a couple of my son's exercise weights on top and allowed it to dry. When the glue was set I finished off all of the cuts and lifted out the ring and the disc at the centre. Then I laid the flexi track onto a layer of PVA in the groove where the ring had been, pinning it down lightly until the glue set then pulled out the pins. Best circle of track I've ever laid and it didn't try to keep straightening out.

Re: Minimum HO radius

Posted: Fri Aug 18, 2017 8:46 am
by b308
It seems you can get it if you shop around, though it may have to come from Germany! I hadn't realised anyone went that tight, I though the Playcraft stuff was bad enough! ... ius-250-mm