Balcombe tunnel

[3] Rastrick described the tunnelling as very treacherous, requiring great caution on the part of the miners working it, as "it swells and effloresces as soon as exposed to the air.

[1] Galvanised iron sheets were fitted to prevent the water falling on passengers in open carriages, but the blast from the steam locomotives and air pressure created by the passage of trains could result in the metal sheets being torn from the structure, creating a serious hazard.

The "railway murderer" Percy Lefroy Mapleton left the body of his victim Isaac Gold, whom he had robbed, in Balcombe tunnel in 1881.

In July 1903 plans were finalised for the boring of a second Balcombe tunnel as part of the scheme to quadruple the Brighton Main Line throughout, but these were never implemented.

The trays consisted of steel decking, gutters and flashings which were installed under limited track possessions.