If a rail track is laid on wooden sleeper with sleeper density of 20, with spacing between two sleepers is 65 cm, and sleeper width of 25 cm, then what is minimum depth of Ballast Cushion:

Transportation engineering or transport engineering is the application of technology and scientific principles to the planning, functional design, operation and management of facilities for any mode of transportation in order to provide for the safe, efficient, rapid, comfortable, convenient, economical, and environmentally compatible movement of people and goods transport. (Source: Wikipedia)

Transportation engineering is also a part of Urban planning.