 The engineer in charge of the construction was Peter W. Barlow and the contractors were Messrs. Hoof & Son . In April 1845 the SER decided that the branch would be double track . A 410 @-@ yard @-@ long ( 370 m ) tunnel was required 44 chains ( 890 m ) after leaving Tunbridge . This was named " Somerhill Tunnel " after the nearby mansion . A mile and 54 chains ( 2 @.@ 70 km ) after leaving Somerhill Tunnel , a 270 @-@ yard @-@ long ( 250 m ) viaduct was required . Southborough Viaduct stands 40 feet ( 12 m ) high and has 26 arches . A temporary station was built at Tunbridge Wells as the 823 yd ( 753 m ) Wells Tunnel was still under construction . It was 4 miles 7 chains ( 6 @.@ 58 km ) from Tunbridge . The temporary station subsequently became a goods station . The first train , comprising four locomotives and 26 carriages , arrived at Tunbridge Wells on 19 September . Trains from Tunbridge had to reverse before starting the climb to Somerhill Tunnel , as there was no facing junction at Tunbridge . This situation was to remain until 1857 , when a direct link was built at a cost of £ 5 @,@ 700 . The old link remained in use until c . 1913 . 
