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Mark Laidlay

Turnout Crossings - How Big?

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I'm looking at building some high-speed turnouts but how big do I go?  Obviously 1:8 is mainstream but can I go to 1:16 and higher?  This is H0 scale, NMRA standards (no P87 etc.) and no moving components in the crossings.

 

Mark in Melbourne

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6 minutes ago, Mark Laidlay said:

I'm looking at building some high-speed turnouts but how big do I go?  Obviously 1:8 is mainstream but can I go to 1:16 and higher?  This is H0 scale, NMRA standards (no P87 etc.) and no moving components in the crossings.

 

Mark in Melbourne

 

Hi Mark,

 

Providing you use the track standards correctly (wheel profile matched to the track standard) there is no limit on the length of fixed V-crossings.

 

For prototype UK bullhead track the longest normally used was 1:20. Longer cast V-crossings are used in modern high-speed junctions. Very long crossings tend to have moving parts such as in a swing-nose crossing.

 

If you use the NMRA H0 standards for long V-crossings, you must use the matching wheels, i.e. RP-25/110 profile (2.8mm wide). You will see adverts that narrower RP-25/88 wheels will run on standard NMRA H0 tracks, but they won't. You may get away with it on shorter V-crossings, but they will bump and derail on long crossings.

 

00 modellers in the UK often make this mistake, for example using 00/EM kit wheels on 00-BF or Peco track standards. They appear to work ok on shorter crossings, but they will drop into and bump on long V-crossings. Using the wider RTR wheels solves the problem, or alternatively if you want to use the narrower kit wheels you need to use a finer track standard such as 00-SF.

 

cheers,

 

Martin.

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I have a drawing for a 1:12 turnout but I would like to try a longer one as well.  Any known drawings for a H0 NMRA standard turnout?

 

Mark in Melbourne

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Templot will go bigger, the pre-selected box goes up to 1-12, use F5 .  I went up to 1-20 with a F switch. but I guess it goes further 

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Hi Mark,

 

Templot is free to use and will print any size turnout template in any gauge or scale, straight or curved: http://templot.com

 

I have created a sample 1:18 template with 30ft straight switch for FB rail and USA-style H0 timbering. Here is the PDF template:

 

usa_style_h0_18_turnout.pdf

 

It's on 3 pages, trim to the red lines to assemble. The rail top is shown in blue and the rail foot in brown.

 

When printing it, make sure to set scaling:none or 100%. This is not the default setting in most PDF readers.

 

There are some other sample USA-style H0 data files for Templot at: http://85a.co.uk/forum/view_topic.php?id=1335&forum_id=10

 

cheers,

 

Martin.

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Thanks Martin, are there any samples using Australian timbering?  Bigger timbers than the US but less of them.

 

Mark

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11 minutes ago, Mark Laidlay said:

Thanks Martin, are there any samples using Australian timbering?  Bigger timbers than the US but less of them.

 

Hi Mark,

 

Sure, it's easy to do that, but I don't know the Australian timber sizes and spacings. Do you have some prototype drawings so that a proper scale template can be created? I believe Australia uses several different track gauges.

 

cheers,

 

Martin.

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I will seek specifications tomorrow.  It's a standard gauge route but I normally model a broad gauge (5'3") prototype.

 

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5 hours ago, hayfield said:

Templot will go bigger... I went up to 1-20 with a F switch. but I guess it goes further 

 

Did it take a whole box of paper to print? Must have been pretty long. 

 

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18 minutes ago, sharris said:

Did it take a whole box of paper to print? Must have been pretty long.

 

Printed full-size it requires about 13 boxes of A4 paper.

 

However, in 00 gauge it is 660mm long and requires only 3 pages.

 

Martin.

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That's big enough when sat side by side with the Settrack point work that many are more familiar with.  I guess 660 mm doesn't actually seem that long, until you decide to make a crossing out of it and realise that it wouldn't fit on a typical 4' x 2' baseboard.

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22 hours ago, Mark Laidlay said:

I will seek specifications tomorrow.  It's a standard gauge route but I normally model a broad gauge (5'3") prototype.

 

The timbers are 10" (by 6" deep if that matters) and angled.  Lengths vary from 9' to the heel to 13'6" at the crossing nose in 6" increments, the longest are 15'.  Points are 16'6" for a 1:9 turnout and check rails are 15'.  Is there anything else I should know?  

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14 minutes ago, Mark Laidlay said:

The timbers are 10" (by 6" deep if that matters) and angled.  Lengths vary from 9' to the heel to 13'6" at the crossing nose in 6" increments, the longest are 15'.  Points are 16'6" for a 1:9 turnout and check rails are 15'.  Is there anything else I should know?  

 

Hi Mark,

 

Timber spacing? Switch heel offset?

 

Otherwise the timbering matches general UK practice. 16ft-6in (straight?) switches match USA-practice if the heel offset is 6.1/4".

 

What crossing angle are you actually looking for? The switches for longer V-crossings will be longer. 22ft?  27ft-6in?

 

cheers,

 

Martin.

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Yep, heel offset is 6.25".  Check rails are 19' for 1:11 and higher.  I would like 1:16 crossing.  I am using Peco code 75 FB rail.

 

Timber spacing is just under 2' from the tip of the 16'6" switch to the heel, 10 timbers all up (for the 16'6" x 61/4" switch).  A to C 1'10, C to G 1' 9", G to J 1'10".  As you say longer switches should be used with a 1:16 crossing.

 

Remaining spacing is 2'1".

 

Thanks, Mark

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Thanks Mark. It seems that you have a drawing? Can you post it? Can you clarify your lettering of the timbers?

 

Ideally we also need to know the blunt nose width on the vee -- 1/2"? -- and its position relative to the supporting timber, the lengths of the wing rails, lengths of the vee rails, etc. Also the rail head width -- 3"?

 

However, using the NMRA standards rather rather Proto87, it can't be an exact scale model. For example the position of the wing rail knuckle will change, and a loose heel at 6.25" offset in 3.5mm/ft scale with 3" rail gives a clearance of only 0.95mm which is insufficient for NMRA H0. The switch will need to be modelled flexible, or if loose-heel the length will need to be extended.  

 

At this level of detail I think we should switch to the Templot Club forum rather than RMweb: http://85a.co.uk/forum/


See also: http://templot.com/companion/timber_spacings_overview.php

 

cheers,

 

Martin.

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