Show curve radius problem - does it occur in TS12?

[obirek]

There is a problem checking curve radius in Surveyor using the tool "Show curve radius". I wrote about this problem some times ago, but now I would like to know if this problem has been fixed in TS12. So, briefly I repeat what was the problem.

After laying a section of a curved track I need to check the track radius. I go to Track>Show curve radius and point to some spot on the track. I get the reading 1360 m (see picture 1 below). Then I move cursor slightly to the left, just about the distance of one slipper and I get reading 1019 m (see picture 2 below). I am near the same spline, so the reading is about the same section of the curve. Yet I get such high discrepancy, 1360 - 1019 = 341 meters. The track looks smooth, but the reading implies as if the centre of the arc moved suddenly almost half of the base board!

This problem occurs in TRS2006 and Trainz Classic 1&2. I believe it also affects TS2009, but I am not 100% sure, as I haven't used the latter for a long time. Is this fixed in TS12? Please, those who use TS12, let me know.




Picture 1 showing radius of 1360 m

Picture 2 showing radius of 1019 m.

 

[Dermmy]

Railway curves are spirals (more or less), but the point is that they are not circular, so the (nominal) radius constantly changes as you move around the curve. That said though the Trainz 'get radius' tool has always been a bit flaky, you will even get different results clicking in the exact same place. I stopped puting any reliance in that particular tool long ago....

 

[cascaderailroad]

The way I use that cool tool, is to put your mouse on the outer edge, of in side of the curve spline point circle. If you use the center of the spline point circle, the measurment sometimes displays a really wacky reading.

http://i525.photobucket.com/albums/cc339/cascaderailroad/Screen_007-18_zps3c869161.jpg

 

[bl4882]

Hi Obirek,

In the prototype, curves ease from straight to curve and back again according to a cubic spiral, that is, from straight to the circular curve gently. Someone at N3V had the bright idea of making curves in Trainz do just the opposite. Instead of going from a gentle to sharp curve, it goes the other way round. Another veteran has said this is a bezier (sp.) curve. Not sure of the spelling and it has nothing to do with women's undergarments. In any event, it is the reason for myriad curve templets on the DLS. Route creation at the track level is the art of conquering Surveyor. The curve tool will give a decent guestimate of the degree or radius of the curve. But lay your curves out with one of the templates to get a reasonable approximation of a prototype curve with a visually acceptable representation of an easement. With a good deal of effort you can make your track look real.

Bernie

 

[obirek]

Hi Obirek,

In the prototype, curves ease from straight to curve and back again according to a cubic spiral, that is, from straight to the circular curve gently. Someone at N3V had the bright idea of making curves in Trainz do just the opposite. Instead of going from a gentle to sharp curve, it goes the other way round. Another veteran has said this is a bezier (sp.) curve. Not sure of the spelling and it has nothing to do with women's undergarments. In any event, it is the reason for myriad curve templets on the DLS. Route creation at the track level is the art of conquering Surveyor. The curve tool will give a decent guestimate of the degree or radius of the curve. But lay your curves out with one of the templates to get a reasonable approximation of a prototype curve with a visually acceptable representation of an easement. With a good deal of effort you can make your track look real.

Bernie

I have no problem plotting track geometrically. I don't use templates, as they are not flexible enough. I use the ruler in Surveyor and a calculator only. But sometimes I need to pull inner splines to emulate a parabola connecting straight and arc which is tedious to plot manually. If I get four different readings it can be difficult task. I am sure this has nothing to do with the shape of real railway track. Be it spiral or not, track cannot jump sideways few hundreds meters between two slippers or no train would be able to run on it. Track in curves tighter than 600 meters can break after welding. But this is fine. I just wanted to know if the same problem exists in TS12. I assumes the answer is : Yes.

Many thanks to you and others for your quick and thoughtful answer.

 

[obirek]

Hi Obirek,

In the prototype, curves ease from straight to curve and back again according to a cubic spiral, that is, from straight to the circular curve gently. Someone at N3V had the bright idea of making curves in Trainz do just the opposite. Instead of going from a gentle to sharp curve, it goes the other way round.
Bernie

This was most unfortunate decision. It is hard to understand why Auran didn't do research on a topic that is discussed in so many text books about railroads. Few years ago I bought myself a book titled "Railroads", published by Warsaw Polytechnic in Poland. In this book, in second chapter, there is everything a railway engineer needs to know about track geometry. If I could read this, why Auran could not?

Once this problem has been "fixed", it looks like there is no hope for an improvement and we are stuck with the faulty model forever. This is bad news for future generations of rail fans.

 

[cascaderailroad]

It is fairly easy to get a smooth curve, with lead in, and lead out easements.

PM me if you need explanation on how I do it.