|Big radius curves and transition curves, by Dr. Norbert Aust (Switchdoc)
| Read | Write comments: 10
||Posted Sun Apr 20 2003 10:47pm
Some remarks up front:
(1) I am not a native speaker of English and may stumble with some of the railway related vocabulary. If there are some bad mistakes, please let me know for I am eager to learn (but be gentle, usually I can't stand criticism).
(2) This article is dedicated to the somewhat advanced user of the surveyor tools. Refer to the very comprehensive articles of John King in this section if you need of instruction.
Now we set to work:
Out in the real world of railways - I will call this nature, even as it is not pure nature - curves are characterised by large radii and transition curves. Both give very elegant looking lines that I appreciate so very much to look at.
Unfortunately Trainz designs curves somewhat different from original railway usage. If you connect two straight pieces of track even if placed to match the rquirements of a circular curve Trainz tends to have sharp bends at the beginning of the curve and having large radii in the middle. In reality it is just the other way round, a curve has to start with a large radius which is decreasing as we move along the curve. Therefore we have to force Trainz with some amount of effort to do what we want it to do.
Of course, there are some tools around to build curves but as far as I can see there is nothing satisfactory to build a curve of 1000m radius with.
If you are building a line based on a map - as I do - you usually have one end of track where you want to continue with a curve, with data being radius and deflection taken from the map.