Decorative image

At a glance

Client/project partners: London Underground

Status: Complete

Location: London



Works included the installation of heating and cooling plant, ventilation systems, fire protection systems, services, and BMS and control – as well as extensive tunnel fit-out and traction power (including 22kV cabling) works. Minimising safety and operational service risks is paramount, so every installation has been planned and rehearsed in the detailed Navisworks digital model.

Complex engineering

CHt’s scope was to undertake the design, installation, and commissioning of the complete MEP services.

The vertical alignment at Nine Elms was reconfigured with a hump profile to increase rolling stock efficiency using natural acceleration and braking. Firefighting lifts installed at Kennington Green and Park provide the emergency services with access at track level. Additionally, our design team developed a heat-recovery solution in the tunnel segments that is adaptable to seasonal change for year-round energy efficiency – just one of the many initiatives that led to the project receiving a CEEQUAL award.

Because of the unique arrangement and size of this project it was necessary to treat the development as 4 individual projects, each with a different project team who in turn where managed by an overriding MEP Senior leadership team. This ensured a common approach to the delivery processes and ensured best practice was shared by all and ensured from a client perspective the various project was seen as one.

The installation of the MEP services was carried out by a number of selected subcontractors as well as direct CHt labour, who undertook the electrical installation at the stations. At peak 200 direct delivery operatives where utilised on site at any one time, total MEP operative levels across the site peaked at 600.

Added value to clients

The following specialist systems were also installed

Tunnel Ventilation Fans

Consisting of 16 line wide fans across 8 separate shaft structures. - Fans ranged from 30m3/s to 120m3/s and were controlled from the Northern Line main control centre at Highgate via manual intervention utilising 150 pre-programmed event scenarios, which were aligned with the various train positions within the tunnel when a fire would occur.

HV Substations and Track terminations

A new infrastructure system of HV distribution off the London Underground generating network was provided. The complete works from design through to installation and commissioning utilised the London Underground QICC process.

Staircase Pressurisation Systems

In total 6 individual and unique systems were provided across the development to support the evacuation of passengers from the lineside. All were interfaced with the tunnel vent system such that door pressures were compliant with multiple evacuation scenarios. The systems in general covered from 5 to 7 levels and included a series of fire lobbies.

Key statistics

5.8 km


65 km



assurance documents