BG ICF Double-Decker --- These are the type of self-generating, vestibuled, non-ac rail coaches that has two levels of passenger accommodation which inturn increases passenger capacity. The use of double-decker carriages, where feasible, can resolve capacity problems on a railway, avoiding other options which have an associated infrastructure cost such as longer trains, more trains per hour or adding extra tracks besides the existing line. Double-decker trains are claimed to be more energy efficient and may have a lower operating cost per passenger. The Flying Ranee, an Intercity express between Surat and Mumbai Central on the Western Railway section still uses these ICF non-ac double-deck coaches, since 1970. Non-ac Double-decker coaches were the part of Howrah-Dhanbad Black Diamond express for many years during the mid 1980s. Two coaches were there right at the middle of the train. But those coaches were withdrawn later for some unknown reason. Type - WGDCZ.