They're both seemingly based around railways. Railcraft makes them and Steve's carts uses them. It allows for very complex rail based farming/mining/transport/etc.I haven't really played around with Steve's Carts, how do they function well with Railcraft?
Item transport. Automated Farming. Automated Mining. Ore Processing. Power generation. Tools and armor. Chunk loading. The main thing that Railcraft and Steve's carts together don't add is a way to transport power. They have to rely on stuff like TE or builcraft to transport power.I could quite easily challenge that "not have anything missing".