Meeting the technical targets

How Siemens Desiro City Class 700 trains meet technical and reliability targets while delivering improved safety performance and value for money.

The all new Siemens Class 700 Desiro City train is the world’s first ‘second generation’ fully digitally-enabled train in passenger service. It provides significantly increased passenger capacity as well as improved safety, security, comfort and economy. This case study looks at how the new trains, delivered as part of Thameslink Programme, met the technical and reliability targets while delivering improved safety performance and value for money.

Meeting the technical targets

The Class 700 has met or beaten all the exceptionally demanding technical targets that were set.

The train is 5% lighter than the set target weight (the target being much more demanding than for previous generation trains) and the train management system is more intelligent, providing additional capacity and functionality. For example, diagnostic data is constantly communicated between the train and the Siemens service centre, enabling the live status of on board train systems to be monitored – and enabling preventative action to be taken. This applies not only for train maintenance systems, but also by processing data through Siemens Digital Operating Centre, station dwell time issues can be highlighted to train operators and railhead information (in terms of profile and adhesion) can be passed to the infrastructure controller in real time. This predictive maintenance capability is another first for a mainline commuter train.

The Class 700 also has built in redundancy designed into the train systems, enabling the train to continue in service for non-safety related faults that can be fixed at the end of the journey, at a turnaround location or at the end of the day when it returns to a depot.

Because the Class 700 has been developed as a platform, with the Thameslink train the first variant, there are a wide range of configurability and performance options to suit the needs of different investors and operators and/or routes. For example, for GTR the train has a full width cab but can have gangway cab; it also has a 100mph capability, although this can be increased to 110mph for future specifications if required.

Measuring service reliability

From July 2016 the number of trains in service has grown rapidly. All trains are now in service and performance has now reached the demanding levels as specified in the contracts. Siemens and GTR are now working collaboratively to achieve a train performance of 24tph through the core.

Although the operator believes that a MTIN (Miles per Technical Incident) figure of 10,000 is required to run a robust timetable, Class 700 is already achieving a figure of 15,000. It is important to note that comparison with other fleets is difficult because Class 700 is fixed formations of 8 and 12 vehicles and is allocated lower mileage values (by a factor between 2 to 3) for the MTIN and miles per incident calculation when compared to trains which have units coupled together.

Continual improvement will drive the train towards zero faults – the ultimate aim of the programme – such that it becomes the best-performing train in its class. To achieve this, items that need to be improved are logged if they happen in service and allocated to a database if they have been seen before. They then enter the ‘Performance Pipeline’ and ultimately lead to either remedial action through software and/or hardware modifications. Nine software upgrades took place in 2017, with six planned for 2018 and these upgrades will continue through the life of the train – much like updates for a smartphone.

Delivering improved safety and value for money


While delivering 40% more passengers per train than the previous fleet, the new lightweight Class 700 platform is more track-friendly (leading to a reduced track maintenance requirement and less impact on track infrastructure) and consumes less energy (reduced cost). Compared to first generation trains, the Class 700 costs 26% less to maintain, 30% less to clean and 40% less to operate (energy and VTAC) – contributing to significant whole life cost savings.


The Class 700’s additional capacity in itself creates a safer wider environment for passengers, clearing crowded platforms more quickly and providing a more comfortable, safer travelling experience. With bright LED ‘daylight’ lighting, the train’s interiors have also been designed with the passenger at the heart of the process, ensuring they don’t feel boxed in or threatened.

With regard to the structure of the train, it meets all the latest, most stringent safety standards, with:

  • A  crush/crumple element at the front of the train to absorb impact
  • A new smoke exhaust system that includes a network of smoke detection for safer environment in case of fire
  • A fast emergency/ rescue plan, making it easier for passengers to escape in shorter time
  • Two cameras are in each car for added security, with a forward looking camera to help police
  • First 12 car driver-only-operated operation in the UK

Setting the standard

Developed to carry three million passengers a day by 2019, 20-25% of commuters will travel in to and out of London on a Class 700 train, which is setting the standards that others will have to follow:

  • The first second generation train
  • The first to go through the latest set of standards and be TSI compliant
  • The first commuter train to operate ATO and ETCS
  • The first train to feature ‘pit stop’ / predictive maintenance capability
  • The first long fixed-formation, open-gangway, main line train

These air-conditioned, bright and modern trains are wheelchair accessible, have fully accessible toilets and plenty of space for buggies and luggage.

Rail minister Jo Johnson said: “The ambitious £7bn Thameslink programme – sponsored by this government – is delivering extensive infrastructure enhancements, new trains and a new timetable to tackle one of the busiest and most congested parts of the rail network. These major improvements will result in faster, more frequent and more reliable journeys for thousands of passengers across London and the south east.”

Further information

For more information on this Learning Legacy case study please email