Tamil Nadu topped Group D and ended with seven points while Railways came second with five points.
Tamil Nadu will now play Manipur in the second semifinal on May 26.
In the other Group D match, Delhi blanked Mizoram 3-0 to finish on three points.
For Delhi, Mahendra Singh scored in the 53rd minute while Dhiraj Singh and Kabui scored one apiece in the 78th and the 87th minutes respectively.
Meanwhile, Services came from a goal down to hold hosts Orissa 1-1 and in the process top Group C with seven points to qualify for the semifinals.
Services will play Kerala in the first semifinal on May 25.
At the Barabati Stadium here, Orissa surged into the lead when Gokul Oram converted from the spot in the 33rd minute. But Services came back strongly in the second half to level proceedings when Jordon Zoramchhana equalised in the 55th minute.
In other matches, Haryana rode on Abhishek's hat-trick to breeze past Chattisgarh 6-1.
Besides Abhishek, Devendra, Ajay and Habib scored one goal each for Haryana.
For Chattisgarh, Praveen reduced the margin.