Lubrication of rail joints is one of the important items of permanent way works incidental to systematic track maintenance, the lubrication of joints is done for the following purpose -
i. To allow for free expansion of rails.
ii. To reduce wear and tear on the fishing planes of rails and fish plates.
The lubrication of rail joints also called oiling and greasing of fishplates is done once a year for all the joints during the moderate season which does not have extremes of weather (both hot & cold ). Rainy season is also excluded for this purpose. The lubricant used is a paste of workable consistency made of plumbago Kerosine oil and black oil in the following proportion -
Plumbago ( Dry Graphite ) = 5 kg.
Kerosine oil ( IInd Quality ) = 3.5 Liter.
Black or Reclaimed oil = 2.75 Liter.
For 100 joints of 52 kg / 90R or for 125 joints of 75 R / 60 R
Some items only plumbago and kerosin oil is used in the ratio of 3 : 2 for lubrication of fishplates the black oil is however used for oiling of fish bolts and nuts.