Crystal Palce Park became the new home of the relocated Crystal Palace after the Great Exhibition of 1851 in Hyde Park. For a brief period in 1864, the new park became home to an experimental ‘pneumatic railway’ designed by Thomas Rammell. This entailed buidling a tunnel (approximately 10 feet high and nine feet wide) which formed a close seal with the railway carriage. Propulsion was achieved by effectively using the train carriage as a giant piston and using the pressure of air to blow (and suck) ths through the tunnel, emerging into stations at either end.
The tunnel is believed to have been built as semi-sunken with earth cover. The precise route of the tunnel is not recorded but the two stations were the upper at Sydenham Gate and the lower at Penge Gate. At the end of 1864 the tunnel was removed and the route grassed over. Excavations in 1989 showed not everything had been removed and the original trackbed complete with longtitudinal sleepers laid to a standard gauge was revelaed.