the easiest way to start is with industrial craft 2 to double your ore output among other things. If you disable gregtech that is, what i would recommend if you are new.
Thermal expansion can do the same thing as industrial craft for doubling ores, but you need to keep an eye on multiple engines or work with buildcraft pipes. That would make you use several mods at onces, seeing how many types of engines there are these days. With IC2 you got everything in one mod.
The upside on using thermal expansion is tho, once you have the engines, you can use those to power your rolling machine from railcraft.
if you really want to focus on railcraft, make sure the first thing you setup are several coke engines to get a headstart on creosole oil, cause you will need to use that a lot to make rails.