If You live or Have to go towards Vaishali/Noida city center (Blue Line Metro) and your train coming from Ghaziabad/ GZB or Faridabad side then i have a tip that will save time to avoid interchange from yellow line to blue line at Rajiv chowk.
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Most of the trains halts at Shivaji bridge station coming from gzb side, which is outer of NDLS. Leave your train here and cross the line using FOB and catch Metro from Barakhamba Road (blue line) directly. (Distance: 200 mtr).