Almost every issue of Rail Engineer recently seems to have included an article on ERTMS, or ETCS, or a combination of the two. As a recap, for those readers who have been out to lunch for the last couple of years, ETCS is the European Train Control System – a signalling system designed as a pan European system for lineside signalling. The control system knows where the train is by detecting ‘balises’ mounted in the four foot, calculates safe zones both in front and behind it, and instructs the driver through a display in his cab. If safety is threatened, it will even intervene and bring the train to a stand.
ERTMS – the European Railway Traffic Management System – is basically the ETCS described above with all communication being conducted via GSM-R radio. It isn’t actually a traffic management system as yet but the intention is to include this third element at some stage. The GSM-R radio is used to communicate between the signaller and train, thus individually instructing each train driver with a movement authority. It is therefore the best way to keep train headways to a minimum in absolute safety, and correspondingly to get the maximum capacity out of any line.
There are several ‘levels’ of this technology. Level 1 is a basic introductory system which retains lineside signals. Level 2 introduces the radio-control for continuous communication and can permit the removal of lineside signals. Level 3, which is not yet in widespread use, or even properly defined, does not require track circuits as train position information is entirely radio based using balises as points of reference.
Don’t forget CBTC
If this all sounds a little complicated, don’t worry – it is. To further confuse matters, here is another signalling system known as CBTC – Communications-based Train Control aimed primarily at the Metro market. This is also a railway signalling system without lineside signals and can be either track loop or radio based. It is not an international standard and each signalling manufacturer can design its own version, incompatible with any other.
CBTC systems may be more advanced – manufacturers can develop their technology as they wish – but they tend to be used on individual lines of metro systems where there is no crossover with another railway.
Thameslink, the railway between Bedford and Brighton, will, when it is fully operational in 2018, have 24 trains per hour running through its central core. This means dwell times at stations of only 45 seconds. To obtain that level of service, ETCS Level 2 will be employed, supplied by Siemens. Part of the contract is to superimpose automatic train operation onto this.
Crossrail, London’s new West to East railway which will be fully operational in 2019, will also have 24 trains an hour through its core stations. A slightly different solution has been adopted here. Siemens- supplied CBTC signalling will be employed through the core tunnels, switching to older legacy signalling (AWS and TPWS) as they emerge eastwards and westwards to Shenfield and Heathrow / Reading. In time these sections will be equipped with ETCS Level 2.
Time to test
Up to now, all of the attention has focussed on tunnelling and railway construction but, particularly on Thameslink, it is now time to test some of the theories and make sure that the signalling systems will operate as they are planned to do.
So equipment to allow ETCS operation has been installed on the Thameslink route between Elephant and Castle and Kentish Town. A Class 313 test train, previously employed at the ETCS test facility on the Hertford loop, has run through central London completely under the control of the European Train Control System (ETCS) over two weekends of testing. This is the first time a train on the national rail network has run under the cab signalling system in the capital.
Under the control of the Rail Operating Centre (ROC) at Three Bridges, a crucial aspect of the testing was the transition between traditional signalling, and its associated warning systems, and the ETCS-controlled central area. In 2018, the new Siemens Class 700s will not only transition between signalling systems but also between manual and automatic train control.
Paul Bates, Network Rail’s project director, said: “These test runs were an important step for the Thameslink Programme and the culmination of six years of work at our test facilities in Hitchin and in our lab at Southwark.
It was a credit to everyone who has worked on this project that the equipment worked first time, even on the technically-demanding switchover from traditional signalling to ETCS at Elephant and Castle.”
The next step will be the spring visit of a Class 700 train to the test track and more intensive testing with the 313. Then, in late summer, the Class 700 will begin testing its ETCS equipment between Blackfriars and St Pancras International.
Keith Wallace, programme director for train operator GTR, was very pleased. He said: “This is a significant milestone for the programme and will ultimately lead to a 24 trains per hour service which our Class 700 fleet will deliver in 2018.”