Because in most places in the world, the rail is already built. So it's either extend the existing rail network, or try to build a new one entirely. (Apparent

Because in most places in the world, the rail is already built. So it's either extend the existing rail network, or try to build a new one entirely. (Apparently it's something on the line of $10m/mile to add electrification, so presumably building it while building out is less, but not much less.)