The designers of the newly redesigned Mumbai Suburban Rail Map explain their concepts:
Developing a navigation system was a challenge as well as to make it portable, i.e. to fit all the lines in a small size of A5 was a struggle and still make it legible. The current maps floating on the internet somehow do not have an index or an alphabetical listing to search train stations. We are very inquisitive, about who does them? One can argue that the maps are not so huge so they may not require a cross reference alphanumeric grid. We wish to differ on this point. We had done that in our earlier versions of the map but later we dropped it. On one incident while testing, IDC student: Vishnupriya pointed out that why use a criss cross reference alphanumeric grid when the space is so small? She suggested why not just mention a number for each box. The traveller has to just look up the index and then look for the number in the rectangular box. We feel we have made it easy. We would appreciate feedback.