What do the numbered groupings between the 13 Regional Rail Lines indicate?

The numbered groupings between the 13 Regional Rail Lines indicate the specific routes for each train. This numbering system helps passengers identify which train corresponds to which route, making it easier to navigate the rail system. Each regional rail line is designated with a number that represents its unique path and service area, allowing for clarity in scheduling and route management. This is essential for ensuring that passengers can quickly and accurately determine which train they need to board based on their travel destinations. The use of these numbers enhances the overall efficiency of the transportation system and aids commuters in planning their journeys.