Application for creating a 3D map?

Hi,

I'm currently trying to create a 3D map of train-lines for an art project. There doesn't need to be any detail at this stage, I just need to make sure I map the lines in exactly the right place Ideally to the centimetre. I just need to draw it out with lines in a 3D space accurately.

Is there any software that you'd recommend, I just downloaded and started using Autocad 3D but it's such a complex program and the mac version is completely different from the windows one (which all the tutorials are for).
Is there an easier software to use? Ideally one that I can export files from to some rendering/3D software later.

Thanks