laying track on curves.

[melvin]

I understand that laying track on curves has to be right, But how.

I know that tracksetta have a range of sizes, but how do work out which one to give me the curve to fit the width?

 

[Aire Head]

27 minutes ago, melvin said:

I understand that laying track on curves has to be right, But how.

I know that tracksetta have a range of sizes, but how do work out which one to give me the curve to fit the width?

 

 

Do you have a layout plan?

[The Stationmaster]

2 hours ago, melvin said:

I understand that laying track on curves has to be right, But how.

I know that tracksetta have a range of sizes, but how do work out which one to give me the curve to fit the width?

 

All Tracksettas have the radius of the curve marked on them.  As the diameter of a circle is twice the radius doubling the radius will give you the width of a circle or semi-circle (e.g at the end of a continuous run layout) of track.   Thus if you use, say, a 2 ft radius curve the diameter will be 4 feet, if you use a 3ft radius curve the diameter will be six feet.   But when thinking of the width into which you will lay the track you also need to allow for clearance at the edges of hth board or whatever the track is on - so you can't use a 2ft radius curve on a 4ft wide board - it won't fit properly to allow trains to run.  But if you use an 18" radius curve on a 4ft wide board you will have plenty of clearance and if there is a 21" radius Tracksetts it should still fit (I don't lknow if they do 21" radius??).

 

Most British outline models except some small  0-4-0 or 0-6-0s need to be run on curves no sharper than Hornby or Peco 2nd radius - and the radius of that is c.17.4".  If you double 17.5 ((to give a bit of wriggle room) you get 35", just under 3ft so 2nd radius curves might just fit on a 3ft wide board but that would need to be checked.  If you mix your measurements a 2nd radius circle would definitely fit on a board 1 metre wide however most boards are still sold in the nearest equivalent dimension to the original Imperial measurement.

 

Don't forget that the radius will also tell you how far from the end of your layout board a curve has to begin (plus a couple of inches for clearance purposes).  For example with 18" radius curves on a (nominal) dimension 8ftx 4ft  board the curves will need to start about 20 inches from the ends of the board.  This means that 40 inches of the board will be taken up by the curves at the two ends of a continuous run leaving only 4ft 8" for straight track and pointwork between the two lots of curves.  For example I plan to use 3ft radius curves, or larger, if I  can, in a room just over 16ft long but even with 3ft radius I will only have just under 10ft left to fit in a station and the pointwork at one end of it.  The message s taht curves use space both across the layout area and along it. 

 

So when thinking about what will fit into a given space you need to consider several things, viz -

1. How much space do you have?

2. What sort of trains you intend to run which then decides if you need =2nd radius or larger?

3. Can you get the sort of track layout you want into the space you have available at suitably large enough radius for the trains you want to run?

4.  And can you get the sort of track layout you want between the end curves if you are going for a continuous run?.

 

Don't forget a common problem with layout plans is that they turn out needing far more space than you have - which is why you need to start with the space available and work from there.

 

Does that help?

Edited June 23, 2020 by The Stationmaster

[DCB]

I don't really understand the question, but we had a problem years ago in that the layout was 7ft 6" wide X 16ft or more with an operating well.   It was designed and drawn at 1" to 1ft scale but laying the end curves was a nightmare.  In the end we worked out what radius we needed by measuring across from the distance we wanted the tracks from the walls each side and dividing by 2, then we cut a piece of wood a bit longer then the biggest radius and put holes in at the ends exactly to the radius sort of a "Radius Bar".  We made a batten to fit across the operating well to mount the rod. jiggled it so the rod  had the right clearance at the sides and also and left clearance at the shed end and screwed the batten in place temporarily and screwed the rod to it.  A felt tip pen through the outer hole and we had an unambiguous mark to follow.  

We ended up with about four sets of holes in the "Radius Bar" and still have it somewhere. The batten was swiftly recycled.   With a ready ballasted track base the same trick works but you use the actual rod as a guide while laying,  We found tracksettas more useful for checking curves are not too tight than for actually guiding the track while laying as often you want a radius which isn't actually available.

[rab]

You also need to bear in mind that track radii are measured to the centre of the track so you need to add the length of the sleepers to the diameter

Edited June 23, 2020 by rab
Got width and length mixed up

[melvin]

19 hours ago, The Stationmaster said:

All Tracksettas have the radius of the curve marked on them.  As the diameter of a circle is twice the radius doubling the radius will give you the width of a circle or semi-circle (e.g at the end of a continuous run layout) of track.   Thus if you use, say, a 2 ft radius curve the diameter will be 4 feet, if you use a 3ft radius curve the diameter will be six feet.   But when thinking of the width into which you will lay the track you also need to allow for clearance at the edges of hth board or whatever the track is on - so you can't use a 2ft radius curve on a 4ft wide board - it won't fit properly to allow trains to run.  But if you use an 18" radius curve on a 4ft wide board you will have plenty of clearance and if there is a 21" radius Tracksetts it should still fit (I don't lknow if they do 21" radius??).

 

Most British outline models except some small  0-4-0 or 0-6-0s need to be run on curves no sharper than Hornby or Peco 2nd radius - and the radius of that is c.17.4".  If you double 17.5 ((to give a bit of wriggle room) you get 35", just under 3ft so 2nd radius curves might just fit on a 3ft wide board but that would need to be checked.  If you mix your measurements a 2nd radius circle would definitely fit on a board 1 metre wide however most boards are still sold in the nearest equivalent dimension to the original Imperial measurement.

 

Don't forget that the radius will also tell you how far from the end of your layout board a curve has to begin (plus a couple of inches for clearance purposes).  For example with 18" radius curves on a (nominal) dimension 8ftx 4ft  board the curves will need to start about 20 inches from the ends of the board.  This means that 40 inches of the board will be taken up by the curves at the two ends of a continuous run leaving only 4ft 8" for straight track and pointwork between the two lots of curves.  For example I plan to use 3ft radius curves, or larger, if I  can, in a room just over 16ft long but even with 3ft radius I will only have just under 10ft left to fit in a station and the pointwork at one end of it.  The message s taht curves use space both across the layout area and along it. 

 

So when thinking about what will fit into a given space you need to consider several things, viz -

1. How much space do you have?

2. What sort of trains you intend to run which then decides if you need =2nd radius or larger?

3. Can you get the sort of track layout you want into the space you have available at suitably large enough radius for the trains you want to run?

4.  And can you get the sort of track layout you want between the end curves if you are going for a continuous run?.

 

Don't forget a common problem with layout plans is that they turn out needing far more space than you have - which is why you need to start with the space available and work from there.

 

Does that help?

Yes it certainly does, mind you i will have read and digest it further. Thanks for taking the time to respond. Mel.

[melvin]

22 hours ago, Aire Head said:

 

Do you have a layout plan?

No. Not yet just planning stage. But Station Masters response  has given some food for thought.

[melvin]

19 hours ago, DavidCBroad said:

I don't really understand the question, but we had a problem years ago in that the layout was 7ft 6" wide X 16ft or more with an operating well.   It was designed and drawn at 1" to 1ft scale but laying the end curves was a nightmare.  In the end we worked out what radius we needed by measuring across from the distance we wanted the tracks from the walls each side and dividing by 2, then we cut a piece of wood a bit longer then the biggest radius and put holes in at the ends exactly to the radius sort of a "Radius Bar".  We made a batten to fit across the operating well to mount the rod. jiggled it so the rod  had the right clearance at the sides and also and left clearance at the shed end and screwed the batten in place temporarily and screwed the rod to it.  A felt tip pen through the outer hole and we had an unambiguous mark to follow.  

We ended up with about four sets of holes in the "Radius Bar" and still have it somewhere. The batten was swiftly recycled.   With a ready ballasted track base the same trick works but you use the actual rod as a guide while laying,  We found tracksettas more useful for checking curves are not too tight than for actually guiding the track while laying as often you want a radius which isn't actually available.

That looks an idea I could use. My layout has its access down the centre, so there is only fresh air to pin anything to. So, ignoring the spiders (BIG) i will visit the shed for a piece of suitable wood.

[Aire Head]

15 minutes ago, melvin said:

No. Not yet just planning stage. But Station Masters response  has given some food for thought.

 

I would highly recommend making a plan. Look at the space you have and what you want to do with it as that has a massive effect on what you need.

[TonyMay]

Also technically, if you want to be prototypical, curves should be transitioned so that there are no abrupt changes in radius, e.g. from dead straight to tightly-curved. 

[Harlequin]

Another option: If you measure up your space, draw your layout in the computer, you can then print it out real size and stick the paper down onto the boards.

That does involve fiddling around with aligning lots of bits of paper but it allows you to do more complex curves, like inserting turnouts of different radius into curved track and transition curves, as Tony mentions.

 

P.S. I've got my radius bar hung up in my shed - I'm never going to lose it!

 

[melvin]

Been having a look at this curve problem of mine. I am restricted in width 6ft, not length 16ft. Also this curve has to be laid on the Lifting Flap. The layout is OO. 

Up & Down Mains. Running pacifics

A dummy lay down looked as though it might fit except  it did not look right where the curve meets the track on and off the flap. Tonymays comment on transitional curves gave me an idea. I lifted the track on the approach, replaced with a new length and created the transition. ( left Side) Connected another length of track, wired it and ran a loco over it seemed to work, and it looked nice and smooth through the transition. The other side may be more difficult. I will be back.