Xtrkcad

Xtrkcad is a model railway design tool. It is free to download and is very useful for scale design. I have used it in a limited form but once you have got the hang of the interface it is very good, and you will find it very easy to produce track diagrams quickly.

It has multiple scale options, set track packs for download, flexitrack drawing (including calculation of possible curves), incline calculation and many more features.

There are also online tutorials available on the web which are a must see.

It is available from http://www.xtrkcad.org.