Every devlopment always has a catch. The more a govt tries improve situation the more it attracts migrants. Any city can provide adequately for a limited no. of ppl. Even if slum dwellERS are rehabilitated, there would soon be a fresh batch to reclaim railway property as theirs. Considering only unreserved traveller even taking 10% migrants each train to Delhi easily brings 10 ppl per coach. Now multiply it with no. of unreserved coaches, no of trains and no. of days.