repairs to the roof and windows, and a repaint. Tunnel works A development by the Tesco supermarket chain turned the cutting on the London side of the station into a tunnel by the use of large concrete ring segments to form the tunnel profile. The space on top of these segments was filled in to form a ground surface on which the new supermarket was built. Service interruption At 19:35 on 30 June 2005, of tunnel roof near its eastern end collapsed, depositing broken tunnel segment fragments and many tonnes of infill material on the track. News pictures showed that the concrete segments adjoining the hole, which were still in place, appeared to have bowed downwards where two segments met. A Marylebone-bound train was standing at the "up" platform when the tunnel collapsed. Its driver saw the collapse and raised the alarm, so all rail traffic was stopped. No one was injured. A "down" train that had left had to make an emergency stop between stations and go back to Denham Golf Club to allow its passengers to alight. Again, no one was injured. Service restoration and line centenary Following work on removing infill material and various concrete segments, both those that actually failed and those that were judged unsafe but had not actually collapsed, the trackwork and signalling system were restored. Train services resumed from start of the normal timetable on Saturday 20 August 2005. Gerrards Cross railway station had its centenary in 2006. This was celebrated with two London, Midland and Scottish Railway steam locomotives, Class 8F 48151 and Jubilee Class 5690 Leander, hauling trains between Marylebone and High Wycombe. Service The Monday - Friday off-peak service consists of: 4 trains per hour to 1 train per hour to 1 train per hour to 1 train per hour to 1 train per hour terminates The station consists of two platforms, with a turn back siding just west of the station to allow trains to terminate/start at Gerrards Cross. As recently as 2011 a single weekday service to started from Gerrards Cross, running non-stop from . An equivalent service departed from Paddington, and ran non-stop to Gerrards Cross. These trains traversed the now closed former main line between Northolt Junction and Old Oak Common Junction, in many places reduced to a single track. This section was used more frequently by freight and waste trains, and also diversions during engineering