Above: the Grantham (eastern) portal of Gonerby Tunnel, a photograph thought to be dated 2nd May 2006. The signs indicate the beginning of a permanent speed restriction of 60 or 75 mph depending on the type of train, and advance warning of a 30 mph speed restriction for all traffic on the route to Boston, diverging to the right over the Allington chord. © Copyright Donnylad, licensed under the Creative Commons Attribution-Share Alike 2.0 Generic license
by Eric Jeyes
Gonerby Tunnel, 561 yards in length and opened in 1850, is on the Nottingham line two miles north west of Grantham.
By 2016 the track through the tunnel required renewal. The photograph and description below are by Eric Jeyes, a railway civil engineer based at Peterborough who at that time was part of the team responsible for managing track renewals in the Grantham area.
Photograph by Eric Jeyes
This photograph shows tamping after a track renewal through Gonerby Tunnel in 2016. Tamping is a mechanised process in which a specialised machine lifts, aligns, and levels the track by compacting the ballast beneath the sleepers.
Note the temporary site lighting through the tunnel, hung on brackets that were installed along the tunnel wall as prep work before the relaying work started.
Also, the concrete cable troughing route, temporarily removed during prep works. The troughing was stacked at each end of the tunnel as seen here, troughing on the left and lids on the right. It was re-instated during follow-up track possessions. The cables had been temporarily lifted and suspended on brackets installed along the tunnel wall during prep works.
The traffic cone, in the background towards the right-hand side, was used to mark drainage catchpits, to avoid any accidental damage during excavation and re-ballasting works.
For tunnel works, we would normally have a large industrial fan unit at one end of the tunnel during the track removal, excavation, re-ballasting, and relaying phase of the works, to help reduce the build-up of fumes and dust.
Above is the Airforce 200 Unit, supplied by Manta Rail Services Ltd., on trial at our Peterborough Depot. It was manoeuverable enough to be able to get on to track easily from a nearby access point, but could also be lifted into an open rail wagon to take to site, and then unloaded near to the tunnel portal by excavator-type rail plant, using a lifting hook. Obviously we had to take account of any prevailing wind direction when choosing where to site it. They were quite efficient on shorter tunnels, such as Gonerby. On longer tunnels they could be moved into the tunnel, nearer to the site of work.
Forward to Relaying the Down Main Line at Grantham South
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