Midland Mainline Electrification News
Network Rail and Alan Baxter Associates gave a presentation to the DVL CRP meeting in December 2014.
This section of the ex-North Midland Railway is particularly important from an environmental point of view, not just because it passes through a World Heritage Site, but also because it is one of the earliest main-line railways (opened in 1840), was built by the foremost railway engineers (the Stephensons), and well-built so that it has survived largely intact.
Many of the bridges and structures are listed grade II or II*, including the cutting through Belper and the portals of Milford and Toadmoor Tunnels (the interior of Toadmoor Tunnel is not now listed).
An explanation of some of the work that needed to be done was given. It was emphasised that no decisions had yet been taken as to how the this was to be done, and a number of options were being explored:
Clearance is needed under bridges and in tunnels to allow the overhead electric wires to be suspended clear of the trains, but without risk of contacting the structures. This could be done in one of 3 ways;
- Jacking up the bridge and adding extra height to the abutments. This is not really feasible with stone/masonry bridges.
- Lowering the track bed underneath the bridge. The change in gradient of the track has to be within acceptable limits. For every 100mm that the track is lowered under the bridge, a transition length of 100m is required.
- Demolish the bridge and replace it with a completely new structure.
Each bridge was being looked at individually, and no decisions or recommendations had yet been made. A likely option would be to lower the track in most cases, particularly through Belper cutting, but this would also require reconstruction of the platforms at Belper. If a bridge was very close to another structure, track-lowering may not be possible, because of insufficient distance for the transition. This would appear to apply to bridges under Chevin Road (Milford), Matlock Road (Belper) and Newbridge Road (Ambergate). Lowering the track through Belper from the old goods shed to the river viaduct would allow 10 of the 11 bridges to be retained. This would probably require a lengthy closure of the line, with possible bus substitution between Derby and Matlock, although no recommendation has yet been made on this.
Toadmoor tunnel presents particular difficulties, and work is ongoing to find a suitable solution. It was hoped to increase the line speed through the tunnel.
Current laws require a bridge parapet over an electrified line to be at least 1.8m, which means that all bridges would require parapets to be raised. Also, the top coping must be triangular, so that it is not possible for a person to stand on the parapet.
To avoid the possibility of contact with live overhead wires, all trees and undergrowth must be cut back to be at least 6m from the line.
The overhead wires require support masts at typically 50m spacing, and care will be taken to make sure these intrude as little as possible when crossing underbridges. If the underbridge or viaduct is very long, supports will be required on the bridge, and typically these will be lined up with the bridge piers.
The opportunity will also be taken to remove certain trees in order to open up the view from the train. This is a contentious issue, and time will be taken to find the optimum compromise.
Other work to be undertaken as part of the scheme would include relaying Ambergate Junction for 30mph (15mph at present). The replacement of the footbridge at Duffield was being considered, but there were no room for the lengthy ramps required to make it DDA compliant, and it was not considered desirable to install lifts at an unstaffed station. The Matlock branch is not being electrified as part of this scheme. There will also be a major remodelling project at Derby, which will include the building of another platform.
NR's East Midlands Route Study is to be published in the New Year. It is hoped to undertake public consultation on the electrification design options next year and he hoped that it would be possible to apply for Listed Building Consent in 2016. It is intended that electric trains should be running to Derby in 2019 and Sheffield in 2020.
The presentation paper can be seen Here