Background

Signalling Solutions Ltd was awarded, via Balfour Beatty Rail Projects (BBRP), the contract for the signalling and telecommunications works associated with the Gretna to Annan Redoubling Scheme in Dumfrieshire, Scotland, for Network Rail.

The objectives of the scheme were to remove the worst bottleneck on the Glasgow & South Western Line and provide a new diversionary route for the West Coast Main Line, by redoubling the single line section of the route between Gretna Station and Annan. This would also provide increased capacity for freight movements from Scotland to England.

Project Description

Under the contract, Signalling Solutions were responsible for the design, construction and testing of the signalling and telecommunications element of the project, including the associated civil engineering works, for the reinstatement of the 8 miles of former double track railway between Gretna and Annan stations.

The scheme entailed the provision of 14 new main signals with associated AWS, TPWS and SPT's, 40 new TI21 track circuits, and 2 new crossovers, both incorporating HPSA point mechanisms.

A new domino style panel and train describer system was provided at Dumfries signal box to control the re–signalled area. A new relay based interlocking and domino style maintenance panel was provided within a new REB at Eastriggs. Signalling alterations were also carried out at the fringe boxes at Carlisle PSB on the West Cost Main Line and at Annan.

To communicate between the new interlocking and the control panel, a new TDM system was provided between Eastriggs REB and Dumfries signal box incorporating a data logger.

The civil engineering work undertaken included the provision of new bases for the REB and the new power supply point, drivers walkways, signal and location bases, and an under track crossing. Due to the topography of the line, some of the new signal structures and over half of the 50 new lineside locations required the provision of embankment support frames or embankment retaining works. A total of 50km of lineside and power cable was also installed

The new signalling infrastructure required the provision of 18 new lineside telephones. In order to accommodate this, a new telephone concentrator was provided at Dumfries signal box. The provision of a new platform and a new long line public address system was provided at Gretna Station.

Due to the curvature of the line, three areas of poor siting were provided with TOWS staff warning systems.

The scheme met a number of challenges including maintaining access to the Ministry of Defence depot at Eastriggs and the movement and protection of the lineside cable route and locations whilst maintaining the operation of the signalling on the open line. The existing line had to be slewed for half of the 8 miles to allow the new track to be constructed.

The works were commissioned over a 10 day blockade, with the final weekend incorporating the works on the West Coast Mainline.

PROJECT STATISTICS
Client : Balfour Beatty Rail Projects for Network Rail
Date of Award : March 2007
Date of Completion : August 2008

Gretna to Annan Redoubling