When you leave Howrah, the last SLR carriage is always for military personnel only. No civilians are allowed in there. The door is always closed from the inside, so you have to let them know at the window that you're a defense person. Say "Open it" and then they'll open the door for you. If not, they'll ask you to get in the adjacent general compartment. This tip is really helpful for defense personnel, ex-defense personnel, and their family members who don't want to deal with the crazy crowd in the general compartments. Just a heads up: sometimes the military SLR might be at the front or back, so make sure to check before boarding. In my last trip from Howrah, it was at the back.

Jabal Howrah se nikalte waqt, piche wala SLR hamesha military personal ka bogie hota hai. Koi civilian is SLR mein baithne ki ijazat nahi hai. Darwaza hamesha ander se band rehta hai aur tumhein khidki se ye bolna padega ki "Main defence personal hoon. Darwaza kholo." Iske baad hi wo darwaza kholte hain, warna tumse agle General compartment mein chadhne ko bolenge.
Yeh tip Defence personals/Ex-defence personals aur unke baccho ke liye bahut faydemand hogi jo General compartments ki harkat-gardar crowd mein safar nahi karna chahte.
PS: Kuch chances ho sakte hain ki Military SLR aage ya piche bhag mein ho, lekin woh zaroor mojud hoga ya toh piche ya toh samne. Isliye, chadhne se pehle sahi position check kar lena. Mere last journey mein Howrah se nikalte waqt woh piche end mein tha.