The Western Railway line between Churchgate terminus and Dahanu Road carries about 2.6 million passengers per day, almost 43 percent of the total Mumbai suburban rail traffic. The annual passenger traffic density for the Western Line exceeds 145 million passenger-km per km of route per year. In other words, more than 145 million passengers travel, on average, over each km of line per year. The busiest segment, 60 km between Churchgate terminus and Virar, carries almost 900 million passengers per year. The annual traffic density, about 255 million passenger-km per km of route, is believed to be the world record for passenger rail transport.
Due to its extensive reach across the Mumbai Metropolitan Region, and its intensive use by the local urban population, overcrowding has grown to be a compelling problem (4,700 passengers are packed into a 9-car rake during peak hours, as against the rated carrying capacity of 1,700). This has resulted in what is known as Super-Dense Crush Load of 14 to 16 standing passengers per square metre of floor space.
Yearly more than 3,500 people die on the Mumbai suburban railway track due to overcrowding during peak hours. This is believed to be the highest number of fatalities per year on any urban or suburban railway system. Many of these deaths are caused when passengers cross the tracks on foot, instead of using the footbridges provided for going from one platform to another, and are hit by locomotives. Some passengers die when they sit on train roofs and are cut by electric wires.