Railworks America

Ok you all, I think, or I should say hope that I have a beginners grip on the signalling after watching the vids on Pikes how to's. In the last one, he zipped through creating AI traffic. Does anyone know of any helpful tutorials on creating this? I am sure that if I watched the last video again in super slo mo, I might be able to pick up on it after a time or two. Thanks you all.