The earliest survey was made in 1884 followed by another survey in 1885. Based on these two surveys, a project report was submitted in 1887 to the government of British India. Fresh surveys were made in 1892, and 1893 which lead to four alternative schemes being suggested - two adhesion lines and long and two rack lines. Fresh surveys were again made in 1895 from Kalka to Solan with a view to determine whether a 1 in 12 rack or 1 in 25 adhesion line should be chosen. After much debate an adhesion line was chosen in preference to a rack system.