For modeling steel cable, don't use sewing thread—it has stray fibers that look ratty, especially after painting. Instead, use beading thread. This material is thermally bonded, so there's no fraying. Example product: Beadalon WildFire .006 inch (0.5mm) thick, in black, light grey and other colors. Available at Michael's and most craft stores.

This is the first mainline run without any of the extras.

I've read lots of advice, howto, intro, and helpful things on the internet about modeling railroads.

But nowhere is there any information for the beginner, [ ... ]

I have always wanted to start a blog, but 'starting' it is usually the first stumbling block.  This is true with a 2' by 5' canvas behind me for a [ ... ]