I used to use Anyrail, very intuitive.
I have found SCARM to be much more fun to mess with. Worth the learning curve.
Its for Windows only, and be careful not to download an ad by accident while at SCARM. (they are Google ads, not SCARMs)
The program author, mixey, posts here, answers questions, etc.. Creating programs is his hobby.
The best part is the 3d viewer!
This is just a "sketch"(unfinished) It gets much better!