Initially original speed of ICF coach was 96 kmph since secondary suspension was laminated spring. The design was modified to all coil bogies with longer suspension hanger and weight transfer through side bearers, thereby enabling speed potential to 105 kmph on mainline coaches and gradually enhanced to 140 kmph for Shatabdi, Rajadhani and Janshatabdi coaches as per RDSO report No CWI Vol 1.