You can take a train from Haridwar to Kurukshetra via Ambala Cant Junction (UMB) in around 4 h 32 min.
How to get from Haridwar to Kurukshetra
From Haridwar Junction (HW) train to Ambala Cant Junction (UMB) then train to Kurukshetra Junction (KKDE). 4 h 32 min ₹1,524. From Haridwar bus to Kalaamb then taxi to Kurukshetra. 5 h 42 min ₹1,576. From Haridwar taxi to Kurukshetra. 2 h 34 min ₹2,682. From Haridwar drive to Kurukshetra. 2 h 34 min ₹1,143.