These Wagons are also known as Rapid Discharge Coal Wagons. The type used by Railways is BOBRN type having & underside doors and the one used by Thermal Power Stations has 12 underside doors. The side discharge Type Wagons are called BOBSN.

These Wagons can carry 60 tonnes graded coal and ply in merry-go-round system. The loading is done from the top and unloading is done automatically from the bottom through Pneumatic Door Operating Mechanism activated by rail Side Devices mounted on the track. The electropneurnatic system is actuated from 24 to 32 Volt DC operated Line Side Equipment at the desired place. The Door Operating Mechanism has been successfully developed and are in wide use. The wagons have the same features as other wheeler bogie type wagons used for carrying bulk load.

The side discharge Type Wagons are discharged by manually operated mechanical process.