Amusingly enough, most of this is something we got from the systems before that, or simply other countries :-) Just look at this map: https://pl.wikipedia.org/wiki/Transport_kolejowy_w_Polsce#/m...
See how the rail network is much denser in the western regions? Now compare it to this map: https://pl.wikipedia.org/wiki/Ziemie_Rzeczypospolitej_pod_za...