Bank Station – Escalator 8, 9, 10 & 11 – Civils and Cable Protection

Project: Bank Station – Escalator 8, 9, 10 & 11 Civils and Cable Protection

Client: London Underground Limited – Nominee BCV Limited

Works Value: £500,000

 
Under the auspices of the LULN, L&E Framework D & D Rail Ltd were awarded a contract to carry out the Civils Enabling works for the replacement of Escalators 8 9 10 & 11 at Bank LUL Station.  These escalators were removed and replaced in sequence closing one at a time. Our first task was to protect the cables beneath each of the existing escalators to protect the existing cable routes during the removal process of the life expired escalators.  We protected these cables with Dricon ply fixed to a Unistrut frame which in turn was Rawl bolted to the concrete engineers steps below the old escalator.  We also installed and load tested several pulling points for each escalator to assist with the removal of the old and installation of the new escalators.  This allowed safe removal of the old escalator without damaging the cable run. Once the old escalator had been removed by others we were free to return to site to carry out our civil work. During the period of removing the existing escalator D&D fabricated the structural steel which the new escalator would be sat on.

On our return to site we carried out a full survey of the escalator shaft plotting all levels to produce accurate layout drawings. Once the initial survey was complete we broke out and removed the existing motor base & steels and prepared the engineer steps for the installation of the new steelwork and the Lower Machine Chamber areas for the concrete tension blocks .  The new motor base steels and incline supports were positioned and chemically fixed in position.  These are set to a tolerance no greater than + – 3mm.

Reinforcement bar cages were fabricated and shutters were constructed for the formation of the large tension blocks at the base of the escalator shaft and concrete was placed. The positions of all steelwork and concrete bases were checked for line and level prior to final fixing.

Due to changes in the size of the new escalator we were required to increase the space available in the upper machine chamber.  We achieved this by demolishing existing concrete columns and installing slimmer steel components.  Larger access was required for on-going maintenance programmes so the UMC access hatches ware increased and new floor trays and frame were installed.  On completion of our civil work the new escalator was fitted/installed.

On completion of the new escalator install D&D returned to site to install  the dummy motor box covers around the top and bottom of the escalator run off. Floor tiling was replaced and previously removed stainless steel skirting and handrails were reinstated.

Escalator 8 was the last escalator in this package of work. Due to the time constraints imposed by the London Olympics in 2012, our colleagues at LU approached us along with all other contractors involved with the delivery of this escalator with a view of accelerating the installation.

This type of escalator replacement averages 28-30 weeks in duration from when the escalator is taken out of service to when it is back in operation for passenger use. The accelerated replacement programme was set for 23 weeks. This was an ambitious programme from the outset.

Working with our colleagues LUL and also in partnership with all other contractors undertaking their individual disciplines the team as a whole managed to undertake the escalator replacement in just 19.3 weeks. This is the fastest escalator replacement ever on the London Underground network.

 

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