7 Conclusion and Recommendations

7.1 Conclusions

It can be concluded from the swept path analysis that all substation / crossing locations are suitable, given the capacity of the railway bridges, culverts and watercourse crossings are assessed and the capacity is confirmed for the given loads.  All proposed routes require widening for areas of over-run and improvements to remove obstacles for over-hang.

 

Substation location 3 may be less favourable given the extensive works required for access. This includes:

  • 2145m of permanent access road which accounts for the majority of construction costs
  • assessment of bridge deck and initial approvals from Network Rail and Transport Scotland required
  • removal of the westerly parapet on the road bridge over the railway
  • removal of street furniture including bus stop and signposts
  • additional land purchase to accommodate wide swing required by access vehicle as identified in the swept path analysis

The proposed access route to Substation 3, running parallel to the railway track, would require significant amounts of cut material for the intersection to join the existing road at an appropriate level. This material then needs to be transported offsite. An alternative route has been indicated on the drawings which avoids the large cut volume. However, this alternative route may require additional land.

 

Substation location 8 and 9 are the preferred options given the lower cost of road improvements and permanent access road. Costs for substation location 8 and 9 are lower than Substation location 3 as the new access roads are shorter.  Excluding the new access road, the largest anticipated cost for location 8 & 9 would be the widening at approximately chainage 200, where fill material is required to accommodate over-run.

 

Substation location 8 is less expensive than location 9 as the permanent access road is shorter at 384m compared to 597m.

 

An estimate of the costs for each substation delivery route is presented in Table 8.

 

Table 8 - Substation Access Road Construction Cost Estimate

Substation

Estimated Construction Cost Range

Substation Location 3

£506,243

£862,806

Substation Location 8

£187,111

£278,978

Substation Location 9

£225,646

£348,842

 

HGV delivery to cable road crossing 1 and 2 both require a structural assessment of the road bridge crossing over the railway and the watercourse crossing respectively. If satisfactory, both routes will be suitable for HGV delivery to the cable road crossings.

 

7.2 Recommendations

From the swept path analysis and walkover survey the following recommendations have been made to ensure safe delivery along each route:

  • Topographical data and ground investigation information is required to refine the cost estimate for the proposed permanent access roads for each substation location.
  • Ensure there is no risk of grounding for the preferred delivery route using topographical data.
  • Confirm that any bridge or culvert crossing along the A1 (out with the boundary limits of this report) is suitable for the given delivery loads.
  • An abnormal load assessment of the road bridge crossing the railway for substation location 3 is required.
  • An abnormal load assessment of the culvert for substation location 8 and 9 is required.
  • As part of the temporary works design, a steel plate rated to D400 loading in accordance with BS EN 124 should be designed for undersized or unclassified manhole covers as a minimum.
  • A HGV load assessment of the road bridge crossing the railway for cable road crossing 1 is required.
  • A HGV load assessment of the road bridge crossing the watercourse for cable road crossing 2 is required.

 

Appendix A – Vehicle Loads and Dimensions

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Appendix B – Swept Path Analysis Drawings

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Appendix C – Route Walkover Photographs

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Appendix D – Permanent Road Access Proposal

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Appendix E – Permanent Access Road Cost Estimate

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