Two-tier or Double-Decked coaches for Third Class were introduced first in 1862 mainly in EIR & GIPR sections. The lower deck used to accomodate 50 passengers whereas there was no seats on the upper deck and passengers had to squat on the floor with a maximum capacity of 70 persons. These carriages were heavily used between 1863 & 1903. A replica of that old DD Third Class carriages is kept at Regional Rail Museum, Howrah.