# How to calculate inclined curved train track?

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## How to calculate inclined curved train track?

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## Re: How to calculate inclined curved train track?

 The simplest answer is that the track is just 'too curved'.  To make the geometry work out nicely for a piecewise modular track with a sloped curve like that you'll need to allow the seams to be at odd angles, or make the radius of curvature larger. There is no 'flat helix' that you can easily use to make a curve like that. The same length on the inside of the curve will always be a bigger angle from center of curvature than the outside of the curve so it will always climb 'faster' from the POV of the train. The duplo trains also have solid axles and not a lot of wheel taper which means self-stabilization is limited. -- Sent from: http://forum.openscad.org/_______________________________________________ OpenSCAD mailing list [hidden email] http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org
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## Re: How to calculate inclined curved train track?

 My first thought was that it is impossible but what if you do the following? :Generate the inner rail and the straight part of the outer rail.Place the train with its front wheels at the end of the straight.Repeat: Step it forward a little and keep the inner front and the back wheels on the existing track. Generate a short section of outer track that meets the outer front wheel.Would that not generate a banked outer rail that always keeps four wheels on the rails? Or would it generate a corkscrew and flip the train over?On 29 June 2018 at 21:20, NateTG wrote:The simplest answer is that the track is just 'too curved'.  To make the geometry work out nicely for a piecewise modular track with a sloped curve like that you'll need to allow the seams to be at odd angles, or make the radius of curvature larger. There is no 'flat helix' that you can easily use to make a curve like that. The same length on the inside of the curve will always be a bigger angle from center of curvature than the outside of the curve so it will always climb 'faster' from the POV of the train. The duplo trains also have solid axles and not a lot of wheel taper which means self-stabilization is limited. -- Sent from: http://forum.openscad.org/ _______________________________________________ OpenSCAD mailing list [hidden email] http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org _______________________________________________ OpenSCAD mailing list [hidden email] http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org
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## Re: How to calculate inclined curved train track?

 @nophead, I also thought about something you describe. What probably happens, when the wheels on the back also tough this 'new' outside curve, they will "roll" the locomotive a little, so the front wheels will be lifted again. And so the track is 'not right' (again). That's also what I experience right now. The first & last part of the track are somewhat right, but this middle section is apparently to steep. That's also what NateTG is describing. Reading literature about real trains, this height difference is called cant (crosslevel or superelevation). Here train safety (self-stabilization) & comfort is most important. Also the metal rail could bend a little and so do the train springs. Not comparable with the duplo situation. Thanks for the replies, I'll try a less steep situation. -- Sent from: http://forum.openscad.org/_______________________________________________ OpenSCAD mailing list [hidden email] http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org
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