Page 3 - LMD Vacuum Excavation - Annual Review 2021/22

LMD working on the electrification of Denmark’s railway network
Per Aarsleff A/S is working with Siemens to electrify 1,300km of the Danish state railway network. A key element of this project is the electrification of the Aarhus to Fredericia section which is 108km in length and runs down the eastern side of the Jutland peninsula.
The electrification programme requires the installation of 9m high masts to support the electrical catenary cables. The height of the masts means that 33 bridges will require significant structural change or rebuilding. The masts are located at between 15m to 60m centres depending on topography and track layout.
In November, Aarsleff contracted LMD to undertake the excavations required for the erection of the masts. LMD’s large tracked excavator was shipped across to Denmark and craned on to a flatbed wagon.
The excavator, expertly controlled by its operator, Nigel, has completed up to 50 excavations during each night closure. It has been so successful that it completed its programme of works well ahead of schedule and has now returned to the UK.
As night temperatures tend to fall below zero in Jutland during December and January, there was a danger that the excavated ballast and soil could clump and freeze in the
hose. Consequently, the tracked excavator was fitted with agitators. Agitators are located on the outside of the hose and are powered by compressed air. As the name suggests, the agitator continuously causes the hose to vibrate minimising the risk of a blockage. There are typically three agitators in a set and these are located in areas where the risk of ‘clumping’ is highest, for example at bends.
The agitators were so successful that all new LMD vacuum excavators will be supplied already prepped to accommodate agitators when needed.
Mick Dysart is LMD’s Managing Director:
‘Agitators are not just used in freezing conditions, they
are useful in a wide range of applications including the excavation of clay and wet sand. The new excavators will come with an agitator function pre-wired into the ‘brain’ of the vehicle. The excavator will also require a more powerful compressor in order to deliver the required CFM for the agitator to be effective. Our first agitator-ready vacuum excavator for use on projects in the UK will be with us shortly.’
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