Again, here we are mixing the railways and population. The railway network in India is more or less the same as British rulers had developed long back. There are places which are chosen to create rail junction because of there location on the map, their geography, etc.
That is why some small town also get prominence on the railway map. Indore has been a very big city for a long time. It has excellent road connectivity with major Indian cities. But it has been not on the so-called metro or main routes of Indian railways.
So,...
more... judging the railway facilities of a city by its population, is not a perfect parameter always. This can be understood by the examples of Bina (Sagar), Itarsi (Hoshangabad), and many more stations on the Indian railway map.