Alternative method for gantry move

Costain Skanska – a joint venture between British construction company Costain and multinational construction company Skanska – commissioned UK-headquartered heavy lift and transportation specialist ALE to move a gantry crane over live rails in London, England.

The crane weighed 290 tonnes and was required for demolition work on the HS2 rail project in North London. According to ALE, its client stipulated that the state of the crane could not be altered in any way and that there could be no impact on train operations.

ALE said it developed an alternative methodology to move the gantry crane compared to the usual way in which these types of cranes are moved. For this, it designed a bespoke bracket that lifted the crane from the jacking points underneath the bogies. This meant that the crane’s state was not altered and that its structure was not subjected to stresses beyond its design criteria, which may have caused it to become unstable during the move. This instability was due to two of the crane legs that had the potential to swing now being secured with a pin joint, explained ALE.

The gantry crane move was carried out on Christmas day, 2018, to minimise disruption to the train service. 36 lines of Goldhofer self propelled trailers (SPT) in a 2 x 2 file 18 configuration with the bespoke brackets attached under the bogies manoeuvred the crane approximately 40 m clear of the rails. It was then placed onto a custom mock rail line foundation.

The move was completed in 11 minutes. As it was located in a residential area, to avoid disruption to residents, the team returned a few weeks later to remove all equipment off site.

“We faced more challenges than the usual port cranes moves we perform, which are typically rigid and don’t have the load bearing pressures capped,” said project manager David Trigg. “Because of the complexities involved in this project, it was hugely rewarding to see all of the detailed planning come together. By working with our in-house engineering experts in the UK, our bespoke new brackets enabled the successful and safe completion of the job.”