Well many cities are long that way. This proposal is really skinny... everything 5 minutes walk away from the line. Bombay is more like 1:4 aspect ratio, this would be like 1:1000.
a better model would be a 2d city with a train line snaking back and forth through it, so you get efficient use of land but everything is still 5 minutes away from the line. linear city is more sfnal though :)