What are ' railway sleepers'? How many sleepers are required for 1 mile of railway track?

Railway Sleepers are wooden planks laid across railway tracks; they hold the tracks in position . Between 1, 760 and 2, 000 sleepers are needed to lay 1 mile of railway track . A single sleeper is approximately 10 feet by 10 inches by 5 inches that is 3.5 cubic feet. Wood for these sleepers came mainly from the Sind Forests. As the railway was fast expanding, there was need for more and more trees to be cut. In the Madras Presidency alone, 35, 000 trees were cut annually for making sleepers.