Northern Line Extension

Developing an alternative to the Safety Restraint Net

Between 2015-17, a series of incidents raised safety concerns about the lifting of palletised materials in UK construction. Our engineering team embarked on an imperative: to develop a reliable alternative to conventional Crane Forks with safety restraint nets. The objective was clear – eliminate risks associated with the net and establish a contained, fail-safe solution.

Unusual Application: Shaft Loadout on Underground Rail Projects

While housebuilding and high-rise buildings seemed the obvious applications, our design exploration led us to investigate the application of Crane Forks for shaft loadout in underground rail projects. This involves repeated lifts of palletised materials into deep shafts.

Challenges of Blind Lifts

Consultations with the lifting personnel on the Northern Line Extension project highlighted challenges with blind lifts (a lift where the crane operator couldn’t see the load while lowering into the shaft). Operators often lacked visibility while lowering loads into 40-metre-deep shafts, leading to potential snagging or dislodging of loads. When the crane continued to lower the load, this load had the potential to be completely dropped into the shaft, risking a serious accident.

“The new Conquip lifting cage is incredibly simple to use. It’s just as quick as using the safety net.”
Deividas Matulevicius | Lead AP for Lifting at Battersea, FLO JV

Complication: Unloading in Restricted Space

The Kennington ventilation shaft had a lot more restrictions, as it was a much smaller shaft and they had restrictions over the available space for moving materials. With the Crane Forks Cage design, we had intended that the Crane Forks would unload the pallet from the cage. However, within the confined spaces of the shafts and with limited crane time, this would mean multiple lifts and space to do so. This was just as much about efficiency of crane time as well as space.

“The cage provides a much safer method than a net, the solid walls and cage provides a much more secure method of lifting materials, even during blind lifts into shafts.”
Liam Greaner | Project Managerat Kennington,  FLO JV

Engineering Collaboration led to a Simple Solution

Our engineering design team went back to the drawing board, looking at ways to unload the cage at the bottom of the shaft without having to use the Crane Forks and carry out multiple lifts / crane moves. Following a discussion with the Kennington shaft lifting team, one of the engineers came up with the idea of a ramp, to enable the cage to be unloaded with a pallet truck.

This simple innovation allowed fast, seamless unloading, even within the tightest shafts or where there was reduced headroom and the crane wouldn’t have been able to operate.

Holistic Lifting Solutions

Beyond the Crane Forks Cage, our involvement in the Northern Line Extension project extended to multiple work packages. Our delivery team collaborated across various areas, offering comprehensive lifting solutions alongside site setup and bulk excavation equipment.