You likely haven't travelled our rail system a lot. Only major train stations have the capacity to handle large volume goods, the far majority of train stations

You likely haven't travelled our rail system a lot. Only major train stations have the capacity to handle large volume goods, the far majority of train stations is to small and has no way to grow (because of property, mountains, geography, ..) Also, I don't know exact numbers, but it's likely to assume that more goods need transport in future as well as more people are going to use trains. The capacity is limited, especially in a system that works so well because it has so little delays as well as a whole fallback network. Pretty sure if they start doubling the freight capacity we will start to see more delays for normal train travel, which is literally the last thing they want to see happen