It is a component of permanent way laid transversely under the rails and performing the following functions. 1. To support the rails firmly and evenly 2. To maintain the gauge of the back correctly

The number of railway sleepers required to be placed under the track per rail length is called as its sleepers density. It is generally given by the formula railway sleeper Density = n + x where n = length of one rail in yards and x = excess number of sleepers

Untreated railway sleepers are prone to attack by decay and vermin. The life of untreated wooden sleepers is thus very less. The life of untreated sleepers can be prolonged considerably treatment.

Creep is defined as the longitudinal movement of the rails in the track in the direction of motion of locomotives. Creep is common to all railways and its value varies from almost nothing to about 6 inches or 16cm.

The separation or cutting of rail due to friction and abnormal heavy load is called wear. There are three types of wears of rail, Wear of rails at the Top, Wear of rails at the end and Wear at the side of head of rails.

The rim or flanges of the wheels are never made flat but they are in the shape of a cone with a slope of about 1 to 20. This is known as coning of wheels. The coning of wheels is manly done to maintain the vehicle in the central position with respect to the track.

Prior to survey the available maps of proposed area are studied. This helps in fixing suitable alignment facilitate various surveys work. The various engineering surveys which are carried out for the choice of route of a new railway line can broadly be divided in to three categories Reconnaissance Survey, Preliminary Survey and Location Survey