Top 5 most rated trains in IRI as per I saw.
1. Sampoorna Kranti Express (967 votes, rating score 4.2)
2. Howrah Rajdhani via Gaya (659 votes, rating score 4.6)
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3. Darjeeling Mail (602 votes, rating score 4.6)
4. Mumbai Rajdhani (579 votes, rating score 4.6)
5. Bihar Sampark Kranti Express (545 votes, rating score 3.5)
Correct me if I wrong.