Heathrow Express, UK, Rolling Stock Advisor

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Heathrow Express, UK, Rolling Stock Advisor

Heathrow Express is the rail service linking London’s Paddington station to the Heathrow Airport. Construction began in 1993 and full service started in 1998.

SNC-Lavalin was retained in 1993 to support the specification of the Heathrow Express fleet. We supported the selection of the contractor, Siemens, negotiated the contract and oversaw the build of the vehicles in Spain and Germany. We also provided oversight and assurance on the maintenance services provided by Siemens. 

Between 2002-05, we executed the same role for the Heathrow Connect Train fleet. We produced the concept designs for the half-life refurbishment of the original fleet between 2011-2013, then partnered with Railcare to produce the engineering designs for the new interiors. We have executed a range of other specialist services throughout the service period of Heathrow Express. 


Over our many years on Heathrow Express projects, we have delivered a number of innovative solutions in a variety of areas, including passenger safety and maintenance. 

Improving the platform train interface

Heathrow Express trains and platforms were designed for level access. Complying with the train and platform construction standards led to a gap large enough for a passenger to get their foot through. As a consequence, Heathrow Express experienced operational issues.

The client asked us to undertake a thorough investigation of the platform train interface from a passenger perspective. This resulted in us obtaining a complete understanding of the issues at the platform train interface. These included visibility of the gap, passenger behaviours and train characteristics. All factors were taken into consideration, as well as stakeholder engagement, in proposing a derogation to standards and the development of a solution.

We partnered with the industry supplier, infrastructure owner, station operator and train maintainer to develop a solution that significantly reduced the gap size, sign posted the residual gap, and resulted in negligible risk of platform train contact. This has resulted in Heathrow Express experiencing a major reduction in passenger accidents at the platform train interface.

Maintaining Service Provision

The route between Heathrow Airport and London Paddington is curvaceous and partly tunnelled. Negotiating this route led to severe wear on the wheels and a high risk of major service disruption. Heathrow Express needed the issues analyzed and solutions developed to prevent damage to the trains and infrastructure to minimize service disruption and reduce maintenance costs. 

We instrumented the train and the infrastructure to record the performance of the track and the train at critical locations. Maintenance activities and behaviours of maintenance operatives were also investigated to understand the impact of effective track lubrication on the wheel-rail interface. We also conducted extensive testing within the tunnel to prove the application of friction modifiers had no impact on train stopping distance.

We implemented an innovative approach to remote condition monitoring of the track and lubrication equipment. This provided real-time information on the performance of the assets and the likelihood of the need for intervention. Application of friction modifiers reduced the wear at the wheel-rail interface and reduced the cost of maintenance without affecting the safe operation of the service.


Heathrow Express is a high performer and customers give the service top marks.

Working in partnership with the client and Siemens, we have ensured that the Heathrow Express has consistently been one of the best performing services in the UK in terms of reliability and customer satisfaction. In 2017, Heathrow Express achieved an overall customer satisfaction score of 97% - its best yet.

Key Facts

  • Heathrow Airport Ltd., Heathrow Express Operating Co.
  • 1993 to date
  • London, UK
  • Main Line