Why did forests around railway tracks in India start disappearing after 1860?

Why did forests around railway tracks in India start disappearing after 1860?

In India the railway network expanded rapidly from the 1860s. Due to following reasons forests started disappearing around railway tracks at that time
(i) By 1890 about 25,500 km of track had been laid and in 1946 the length of the tracks had increased to over 765,000 km.
(ii) As the railway tracks increased large number of trees were cut down.
(iii) The government gave out contracts to individuals to supply the required quantity of woods.
(iv) These contractors began to cut trees indiscriminately.