Curves on a 6' x 2' board

[65mike]

Hi all.

Now I have a large layout in my loft and I have a 6 foot x 2 foot board going spare so I thought I would build a small railway something to get the old grey matter working again.

Now no problem with small engines I have 060 tanks and small wagons so not a problem there either.

Now can any off the forum members advise that size cures will fit the board I have used large radius on loft railway for my 462 locos but need to build smaller layout.

Any advise would be much appreciated.

Thanks.

65mike

[RB51]

I have changed your post title so that folk can get an idea of what you need help with.

I am guessing from your text you are asking what radius curves can you get on that layout size?

What scale are you going to be running?

R-

[What About The Bee]

At 2 feet wide?

2 feet × 12 inches/foot × 25.4 mm / inch = 609.6 mm

First Radius curves are 371 mm

No oval is possible in OO.

Perhaps in a smaller scale....

 

[ntpntpntp]

Even in TT:120 you can only accommodate a semicircle of  R1 (267mm radius) within a 2' board.  So only small/short .locos such as the 08 and the J50 which is coming.

You'll need to go to N gauge 🙂 

[65mike]

Hi all.

OO gauge have seen a 18inch wide board with curves but looking like he is using flexi track.

Not my favourite but will have a look into it.

65mike

[What About The Bee]

Hi Mike 👋 

I really must mind my manners!  Hello and Welcome Aboard.

We seem to have a disconnect.  You use the word "curves" and I am using the word "oval".  

Do you want a complete circuit, to go 'round and 'round?  That, to me, is an oval.

Do you want to go back and forth, to include curved pieces of track?  If so, then whatever fits will be fine.

Bee

[ntpntpntp]

28 minutes ago, 65mike said:

have seen a 18inch wide board with curves but looking like he is using flexi track

If you are talking about a semi-circle of track within the width of the board, then consider this:
the radius is measured for the centreline of the track.  You need to allow about 1" from centreline to the edge of the board otherwise the track and/or rolling stock will overhang the edge.  So that means a diameter of 22", or 11" radius to fit your 2' width.  For 00 that's really tight - by comparison 9" is considered the minimum for N gauge and some modern models rquire at least 10.5".  Yes you can bend OO flexi down to that sort of radius (you may need to cut some of the sleeper webbing)  but realistically you can only really expect to get 0-4-0 locos or older 0-6-0s with unflanged centre wheels around such curves.  Depending on the length of the model the couplings may well overhang too far to be usable. 

Edited June 5 by ntpntpntp

[65mike]

Hi all.

Thanks for the welcome Bee.

I want a oval yes straight then round then straight then round probably boring but points will help and sidings too.

65mike

[ntpntpntp]

6' x 4' is the traditional size for a small OO "roundy-roundy" layout and that can accommodate double track. You can go a bit narrower for just a single oval, but  I'd say with only 6' x 2' you're really looking at an end-to-end shunting puzzle kind of thing, which doesn't sound like the type of layout you want?

Edited June 5 by ntpntpntp

[What About The Bee]

Hi @65mike

Oval it is then!

There are two ways to know if this will work.  Analytically and Emperically.

1) Analytically, by Equation

In part 3 of this Hornby Post, I show the equations that I use.  In those equations, I develop the side to side play required. In your case, you know the side to side play (measure it), and can then see if the track radius is too tight.  Be aware that this will be highly dependent upon your ability to measure your locomotives and rolling stock accurately. 

If you want to take this approach, I can invert the equations for you.  

2) Emperically, by Experiment.

You have the board.  Purchase a bit of flex track and set it on the board, to include a straight. Does the locomotive go around the curve?

There are a few things to look for.

2a) Climbing the rail.  If the track curve is too tight, the locomotive may try to climb the rail, as the wheels simply will not fit.  This leads directly to derailment, which will be obvious.  This is non-correctable, a hard limit.  Relax the track radius until this does not occur.

2b) Buffer Lock.  Okay, the locomotive manages the curve, but can it haul carriages and waggons?  As the curve gets too tight, the buffers will come into contact.  This can force rolling stock off the track, as a triangle is formed.  It can also set one buffer behind (!) another, which pulls the rolling stock off the track when straightening out.  One solution here is to remove the buffers, shrinking the minimum curve.

2c) Premature wear.  Your stock should have brass bearing surfaces.  Sure, the kit goes 'round the curve, but at what cost?  Metal axles and tires are going to play havoc against plastic parts.  Brass bearing surfaces will last far longer than plastic.

There is a reason manufacturers, like Hornby, specify the minimum curve radius.  The design work accommodates all of these points.  They calculate the side to side play.  They consider climb.  They examine buffers and they consider wear. 

Yes!  You can go smaller.  Be careful.

Bee

Edited June 5 by What About The Bee

[65mike]

Hi all.

Thanks for the info will have a think and look into what to do next.

65mike.

[Rana Temporia]

If you can get hold of this June’s Railway Modeller there is an oval layout in there on a 2’ x 4’ board called Ipleigh Castle. The person describes how they made the curves from flexi track and he uses a terrier and two short coaches on it. If you use his methods you would have the space for a couple of sidings as well. 

The original Jouef/Playcraft 1st radius were approx 12.75” so not much bigger but designed for HO, although most of my Tri-ang locos navigate them quite easily. They don’t like those small radius points much though!

I think the smallest curves I have seen in OO were on a U shaped layout in one of the magazines with 6” curves. This used a Mainline 03 which apparently navigated them quite easily. 

[threelink]

If it helps to know this I made a layout which incorporated a curve of 7 inch radius. Hornby/Triang and Lima 4 and 6 wheel (flangeless centre driver) locos would negotiate it successfully as would a Lima bogie diesel (Class 25 I think) with nicks filed into the chassis to clear the gears. Bogie rolling stock ran fine (albeit with considerable throw-over) as did short wheelbase 4 wheel wagons - all fitted with tension lock couplings. Long wheelbase 4 wheelers objected unless the tension lock couplings were replaced by older Triang tension locks (the hooks on the older couplings are longer than the newer and the newer would clash on the curve causing the wagons to flip off the track). Six wheel wagons were a no no unless the centre wheel flanges were removed. The track was code 100 flexible and rolling stock wheels were older Hornby (slightly deeper flanges than present day but not so deep as the old Triang "steam roller" wheels). Good luck with your endeavour.

[81F]

If it's just a modelling project to build something, what about an end to end, possibly a shunting type in an industrial setting - ideal for the 0-4-0s. Or you could cut the board in half and have anything up to 12' x 1'. That could give you a branch or industrial terminus with a fiddle yard