What are the advantages the north had over the south?

One under appreciated advantage was the railway system, the north had a much vaster railway network that they contiuned to add to throughout the war and they used it to devestating effect. Where as the south didn't extend theirs anywhere near enough.

The result being that the north could move troops and supplies around alot faster than the south. Not necessarily a war winner, but a massive advantage, no the less.