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  • London Underground upgrade programme
  • Portastor can create rail-gauge buildings to UIC W6-A standards
  • Packaged solutions, ready for simple installation on site
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London Underground upgrade programme

Location: London/South East

Storage Use: 18 robust, secure UPS buildings


The Metropolitan Line of the London Underground is being upgraded with new air-conditioned trains, which will improve speed, reliability, comfort and capacity on this busy line.

To enable the new trains to run on the existing tracks, the current signalling system needs to be ‘immunised’ to overcome electromagnetic compatibility issues between the new trains and the existing signalling system. To immunise the system, signalling components need to be changed, which requires a new power infrastructure at a different electrical frequency. London Underground instigated the Low Voltage Alternating Current (LVAC) power upgrade project to enable the new signalling
systems and power infrastructure to be installed. The signals will be supplied with two sources of power to
protect against power failures. To prevent a loss of power during the switch from one source to another,
uninterruptible power supply (UPS) buildings are needed to bridge the gap during any switchover.


Following a competitive tender process, Portastor was chosen to supply the 18 robust, secure UPS buildings needed for the LVAC project.

These buildings were required within a very short timeframe and Portastor was chosen because it could manufacture the buildings quickly to meet the project’s tight deadlines. Portastor also had the capability to carry out the necessary rigorous design process and to manufacture bespoke buildings to meet the needs of London Underground.

Crucially, Portastor was able to work directly with the UPS equipment supplier, Emergency Power Systems (EPS), managing the supply and integration of its equipment into the buildings. The arrangement gave London Underground a complete packaged solution for the supply of the UPS buildings, making the project much simpler to manage.

Portastor manufactured the 2.4m x 2.4m equipment housings at its 60-acre manufacturing facility in York, UK. Here, the UPS equipment was installed, connected and factory tested by Portastor. The fully integrated buildings were then stored safely at the factory until the sites in London were ready to receive them. Once on site, the buildings were craned into place on prepared concrete pads and connected to the power network and signalling systems.

Off-site manufacture of the UPS buildings removed all construction activities from the hazardous trackside environment, minimising disruption to train services on the Metropolitan Line.

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