HomeRail NewsIn case you missed it - New zone controller technology

In case you missed it – New zone controller technology

Over the 10-day blockade at London Bridge (24 December to 4 January), three new lines through the high level section of the station and the new Borough Market viaduct were brought into use as part of Stage Seven of Network Rail’s Thameslink Programme.

Representing a major landmark for the programme overall, the commissioning also marked a significant milestone for Siemens, with the company’s new Zone Controller system installed for the first time in the UK. This new technology is now controlling signalling operations at London Bridge, with further deployments scheduled for later stages of the Thameslink programme.

The Zone Controllers were installed in relocatable equipment buildings (REBs), the majority of which were installed under viaducts due to space constraints. The controllers provide an input/output module (IOM) interface between Siemens’ Trackguard Westlock interlocking and the trackside infrastructure.

86 trains an hour!

Commenting on the development, Mark Ferrer, Siemens’ director of new technology, said: “Although, at first glance, it may seem a little unusual to introduce a completely new system on such a high profile, much-scrutinised project, the performance requirements of the London Bridge area were such that traditional technology would have been too slow in operation. Network Rail’s specification for the programme demanded that the performance of the interface had to support a peak flow of 86 trains per hour (tph) through London Bridge.”

Independent analysis was commissioned to establish a precise speed target, effectively setting a performance specification for Siemens’ development team to meet.

The Zone Controller developed by the team is an internet protocol (IP) network-based solution, rather than one that operates over a baseband datalink as TFMs (track function modules) would. As fast as a relay solution, the new controller also has a significantly smaller footprint than an equivalent TFM and provides greatly improved diagnostic capability, making any future maintenance requirements simpler, faster and more efficient.

Mark Ferrer continued: “Having been operational for a little over three months now, the technology is already performing well and faster than the target speeds. There’s no doubt that this is a good solution, not only for Thameslink, but also for future Network Rail projects. As a combined delivery team, we certainly set ourselves a challenge by committing to developing a completely new technology for the first time at London Bridge.

But having established its capability on one of Europe’s busiest stretches of railway, we’re confident that in time it will become part of Siemens’ standard solution.

“Developed and delivered entirely within the UK, the creation, testing, proving, installation and commissioning of Zone Controllers is a great example of partnership-working with Network Rail, with the technology meeting many of the requirements of the digital railway concept and the move to IP-based solutions.”

Closer intervals = more capacity

Thameslink, of course, will also see Siemens delivering a European Train Control System (ETCS) solution overlaid with automatic train operation (ATO), these being crucial requirements for the achievement of a reliable 24tph service. These ATO and ETCS solutions will be installed on the Thameslink route through the London Bridge area, enabling all train movements to be controlled automatically from Network Rail’s new Three Bridges Rail Operating Centre on programme completion in 2018.

ETCS will allow trains to use the Thameslink core lines more efficiently by managing the signalling directly to the train through the radio block centre (RBC). The conventional signalling system in the area will be retained, allowing non-ETCS traffic to use the lines.

The train-borne ATO unit will drive the train within the speed and distance limits set by the ETCS system, which will provide continuous automatic train protection (ATP). This allows the trains to be safely managed at closer intervals, allowing a greater throughput of traffic. If the speed or distance limits are exceeded, then ETCS will intervene and return the train to a safe state.

From the automatic train regulation (ATR) within the control system, the ATO unit will also receive a ‘target arrival time’ for the next station, enabling it to fine tune the train’s speed for optimum performance. Once ETCS is engaged, drivers on Siemens’ new Class 700 trains, will accept automatic control on arriving at the ATO boundary, normally with the train continuing on the move, with a transition back to manual control at the end of the ATO-controlled area.

Testing underway

In Autumn 2015, Network Rail completed the first ETCS trials through central London, with the Class 313 test train completing a series of tests between Elephant and Castle and Kentish Town on weekends in October and November.

Mark Ferrer said: “The equipment worked first time and demonstrated the technically demanding transition from traditional signalling to ETCS. Although testing will continue at Network Rail’s ETCS National Integration Facility (ENIF), the next major milestone is testing with the new Siemens Class 700 trains between Blackfriars and St Pancras which is scheduled to take place in August 2016.”

To achieve an operational 24tph timetable, the signalling and control system actually has a design capability of 30tph in both directions, to allow for recovery from any perturbation.

ATO will open the train’s doors immediately as it stops in order to meet a 45 second dwell time – allowing passengers time to embark and disembark before train dispatch. To maintain passenger safety, door closing will be manually controlled by the driver.

In the unlikely event of the on-board ATO becoming unavailable, the system will allow manual driving with ETCS train protection. Further levels of back-up operation use lineside signals with Network Rail’s existing train protection and warning system (TPWS), or special provision to allow the driver to continue at slow speed.

Mark Ferrer concluded: “The Thameslink project will be the first operational application of full ATO functions over ETCS, certainly in the UK, and possibly the world, and is Siemens’ first operational application of ETCS (both for the infrastructure and on-board) in the UK.

“The introduction of ATO represents a vital part of the high-capacity timetable planned for the route and means that every train runs at the optimised speed profile, performs accurate stopping, and advises the driver to adhere to strict station dwell times.”


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