Meeting the engineering and logistical challenges

How new Siemens Desiro City Class 700 trains move large volumes of passengers efficiently, effectively, safely and comfortably

Innovative Design

The innovative design of the second-generation Class 700 Desiro City sees the introduction of a completely new train platform, making it a unique combination of a commuter and metro train, developed specifically to meet the needs of high-capacity, high-frequency routes.

Throughout the design phase, Siemens worked with specialists in operation, maintenance, cleaning and serviceability to make sure that every aspect of the train’s design was optimised for the operator, maintainer and owner.

This platform is based around a revolutionary, lightweight bogie design, which contributes to the train being 30% lighter than the outgoing vehicles. This reduced weight in turn leads to significantly reduced energy consumption, lower carbon dioxide emissions and reduced wear and tear on the rails and network infrastructure. For the train operator, track access charges are therefore commensurately lower.

As a ‘Second Generation’ train, it is software driven, and with all services and cabling in the roof (rather than vehicleend in cabinets) and all the mechanicals below, not only is the train lighter, but the floor area is also available to comfortably maximise seated and standing passengers. Although Siemens was named preferred bidder on the Thameslink contract in June 2011, at its own risk, the company had already begun development work on this new train platform, with two prototype (pre-series) trains having already been built and tested at that stage to de-risk later development work. As a consequence, the specific work on the Thameslink trains was able to begin in October 2011, 18 months ahead of agreeing contracts in June 2013, enabling the new second generation train able to be introduced into passenger services much more quickly.

Even though this is a completely new train and therefore a hugely complex development programme, all the development, engineering, testing, production and commissioning work has been delivered on or ahead of schedule at every stage.

Logistically Complex

As one of the largest train orders ever placed in the UK, the logistical challenges of manufacturing and delivering the 115-strong fleet, comprising 1,140 vehicles, were considerable. To meet the demands of the programme, not only was the extremely close collaboration of the entire team (both within Siemens and across the whole supply chain) essential, but also a fundamental review of the manufacturing process was required.

As a result of this review, Siemens re-designed its production facility at Krefeld, the company’s manufacturing plant in Germany, without which the volume targets could not be met within the required timescales. There was also significant investment at the test track in Wildenrath in Germany, with new longer sheds being built to support the commissioning. The redesign at Krefeld led to the train manufacture becoming a modular process, with the production team able to work on the roof, interior and underfloor of the train at the same time, rather than consecutively. This new process means the train passes through the production process on its journey to completion with construction much more modular, such that each module is pre-tested and then delivered to an assembly line.

To keep pace with the delivery schedule, Siemens routinely manufactured two cars, every day, for thirty months of the build programme – with as many as four cars built per day at the peak.

This relentless production cycle was known as the ‘beat rate’, the pulsing heart of the programme, which was fuelled by 80 tonnes of materials being delivered every day by over 140 different suppliers from as far afield as China and including numerous suppliers in the UK – all of whom had to fully buy-in to this major change to their traditional working methods.

Given the logistical complexities, no two days were ever the same for the Siemens team. To maintain the beat rate, problem-solving had to happen every day, quickly, efficiently and collaboratively, with Siemens’ introducing a QA system for 40 of the programme’s most critical suppliers to ensure continuity and consistency of the manufacturing process.

It was imperative that the beat rate was maintained, as any interruptions or delays would have a significant knock-on effect to the rest of the programme – which required trains to move from the factory, to the Siemens test track in Germany and then to the UK for testing prior to delivery to the customer, Govia Thameslink Railway (GTR).

Capacity Challenge

Given the Thameslink Programme requirements for capacity enhancement, Siemens not only had to provide extra capacity on each train, but also to keep the station dwell time to 45 seconds – thereby ensuring that the flow of 24 trains per hour through the core area during peak times could be consistently achieved (almost double) the number of services prior to the programme starting).

This requirement helped shaped the train design, with passenger access, egress and flow through the train all critical considerations. As a result, the train is fitted with wider, fast-operating doors as well as wider, more open entrance areas, vestibules and aisles to help passenger flow. This creates a very light, open and airy environment for passengers, all of which contributes to a feeling of safety and security.

At peak times, 2,000 people will board and leave the train in peak hours, with trains arriving at stations every 150 seconds, reflecting metro-like performance. To maintain this timetable, each train has a maximum of 45 seconds to come to a stand at the station, open its doors for 30 seconds for passengers to embark and disembark and then close its doors and depart. This is the fastest dwell time on the UK mainline.

The Thameslink Programme will also be a first for the signalling system used, with Automatic Train Operation (ATO) and the European Train Control System (ETCS) in operation together for the first time on the UK mainline. This enables the 24 trains per hour (tph) service to be achieved (with scope to increase this to 28 tph), with the train operating fully automatically through the core area and then switch seamlessly to interface with Network Rail infrastructure outside the core.

World First

Representing a world first for the use of this technology on an urban, high-density railway, on 17 March 2018, Thameslink train 700019, running in passenger service, drove through the Thameslink core in Automatic Train Operation under ETCS Level 2.

The train drove automatically, with full protection from the ETCS radio-based signalling system, through one of the most important sections of London’s railway network, transitioning into ETCS Level 2 on its approach from Kentish Town and back to conventional signalling between Blackfriars and Elephant & Castle.

Thameslink is using Grade of Automation 2, with the driver checking the platforms, closing the doors and initiating departure from each station; the Class 700 ran between stops using the ATO and cab signalling, opening the doors automatically at the next station.

This marked the culmination of a programme which has been running continuously since the start of the Thameslink Programme, with the cutting-edge technology enabling GTR to run the high-intensity Thameslink service of up to 24 tph.

The project partners ran nearly 200 night and day shifts of testing since April 2016 when dynamic proving trials began at Network Rail’s ETCS National Integration Facility at Hertford North. Testing of ATO over ETCS started in November of that year. ETCS Level 2 has been overlaid on the conventional lineside signalling through the Thameslink core, with short blocks allowing trains to operate at closer headways.

Both GTR and Network Rail had to demonstrate to regulator ORR that it had amended its Health & Safety Management System to operate trains in passenger service using both ETCS and ATO. It has also started a comprehensive driver training programme ready for the launch of full ATO working between St Pancras and Blackfriars at 20 tph from May 2019 and through to London Bridge from December 2019.

The first UK mainline train running in ATO for passenger services was a truly momentous day for the Thameslink Programme and the wider industry teams involved and underlined the combined efforts of the whole Thameslink delivery team and wider supply chain.

Further information

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