Bhai, Train No.12345/46 Saraighat Exp. & 15959/60 Kamrup Exp. ka loco change hota hai, matlab Electric Loco me Howrah se New Cooch Behar tak aate hein aur New Cooch Behar me Electric Loco k jagah Diesel Loco ko replace karke aage journey karte hein.
Tumhare img train me ye possible nahi ho sakta. Kyunki tumhare train ko Cuttack me Loco Reversal karna padega, aur iss process mein kam se kam 15-30mins ka time lagta hai. Loco Reversal mein Loco ko train k ek end se detach karke uske dusre end mein...
more... attach kiya jata hai.
I hope, you'll understand it.