HS2 4,600t M6 viaduct slide: incremental launch lessons for project engineers
Reviewed by Tom Sullivan

First reported on New Civil Engineer
30 Second Briefing
HS2 contractors have completed the final slide of a 4,600t viaduct section across the M6, moving the structure into position without a full carriageway closure in what they describe as a UK first. The operation used incremental launching techniques to shift the preassembled deck over live traffic, relying on carefully sequenced night-time lane restrictions instead of total shutdowns. For future motorway-rail interfaces, the method signals wider scope to build major spans offline and slide them into place, cutting possession times and temporary works demands.
Technical Brief
- Method offers a template for future rail–motorway interfaces where full closures are contractually or politically constrained.
Our Take
The 4,600t HS2 viaduct slide over the M6 sits alongside other complex HS2 interface works in our coverage, such as the Greatworth green tunnel road realignment, underscoring how much of the UK scheme’s risk is now in live-asset interactions rather than greenfield sections.
National Highways’ involvement in the related 17-hour M6 slide operation suggests the methods proven here could become a reference approach for future motorway overbridges in the United Kingdom, particularly where full closures are politically or operationally difficult.
Across the 272 Infrastructure stories in our database, HS2 appears repeatedly as a driver of disputes and compensation cases (for example the Cemex UK land ruling), so technically successful manoeuvres like this viaduct slide may help HS2’s narrative on engineering competence even as land and cost pressures continue.
Prepared by collating external sources, AI-assisted tools, and Geomechanics.io’s proprietary mining database, then reviewed for technical accuracy & edited by our geotechnical team.
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