I travelled in Middle berth in Sleeper coach last week. If we open up the window slightly that's enough...air circulation was superb throughout the journey through the window for middle and lower berths (refer image)....and the new LHB coaches were well maintained, neat and clean....the new type ladder was very comfortable to climb to middle, upper berths and there are no tube lights instead all are LED lights...those lights were also nice and its brightness was higher when compared to tube lights...by using these LED we can save power also...Overall journey was comfort, smooth and worth for money....i would recommend to take SL class instead of AC classes in Pothigai and nellai exp...!!