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With Alstom's TCS contract for the WCML cancelled, it's ctrl.alt.del for ERTMS
Our report (Modern Railways News March) that the European Rail Traffic Management System(ERTMS) for the West Coast Main Line, more properly TCS (for Train control System), was to be sidelined had my chums at Alstom Transport Information Solutions on the ‘phone PDQ. ‘News to us' they said, while calming down worried staff.
Interesting, because Mr Editor Abbott was given the information in an interview with Network Rail Chief Executive John Armitt on 21 January. And in mid-April Network Rail did indeed give Alstom formal notification that the WCML TCS contract was to be terminated.
This came to light when Informed Sources reported that Network Rail had told it's staff not to speak to Alstom people ‘in case it affects the settlement'. What ‘settlement'? Well, it soon got round the industry that Alstom had notified its staff that the TCS programme was being terminated, resulting in 129 redundancies.
While I say Alstom's ‘contract', it was really a series of authorisations to carry on spending. Awarded in July 1998, the £440 million deal was to be funded in stages, starting with a nine month project definition phase.
That seemed to set the pattern, because when the implementation phase started, Railtrack and then Network Rail authorised the funding three months at a time. Perversely, the contract is now being terminated after the first six months extension'
Since 1998 just over £200m has been spent on the TCS contract. What has it bought?
Most of the hardware is on the Alstom Old Dalby test track. But travellers on the WCML can see masts for the GSM-R radio base stations springing up.
Under the original TCS proposal, GSM-R digital radio was going to link radio block centres with the trains to provide ERTMS Level 3 moving block signalling and 140mile/h running by 2005. Subsequently TCs was de-specced to Level 2.
More about GSM-R, and whether it can do what it says on the tin, separately.
Meanwhile, Alstom is pressing on with its separate contract to provide the Tilt Authorisation & Speed Supervision (TASS) system. TASS ensures that the Pendolinos and Super Voyagers will tilt only when it is safe to do so.
Clearly since it is a case of ‘no TASS no tilting trains' the system is non-negotiable. TASS shares some of its hardware and software with TCS, in particular the track mounted balises.
TCS, in its final version, was effectively ERTMS Level 2 System C in the ERTMS Programme Team (EPT) parlance. This means cab signalling with lineside signals retained.
However, EPT reckoned, and independent consultants concurred, that the only form of ERTMS that came even close to making a business case was Level 2 system D – cab signalling with no lineside signals. And that is the official way forward.
Even that business case is pretty tenuous. And as you know German Railways has already said that ERTMS is a Euro-boondoggle and if Brussels wants interoperability it can pay for it.
To take ERTMS forward in the UK the Strategic Rail Authority is setting up the Single National ERTMS Programme (SNEP). And it was SNEP that killed-off TCS.
Despite what some expert witnesses told the Joint Inquiry on Train Protection, and others who knew the truth failing to speak up, ERTMS is not available here and now. Development has years to run and will not be easy.
We have had three teams working on it in the UK . Alstom with TCS, the ERTMS Programme Team set up by SRA and Railway safety, as was, to provide industry's response to the surreal Joint Inquiry recommendations plus Network Rail's expert project team.
Chairman Mao may have wanted a thousand flowers to bloom: SRA knows that the only way to progress ERTMS is through a monolithic state programme with all available talent working towards a single goal. So, with SRA Chairman Richard Bowker in autocratic mode, the TCS development work will be migrated into SNEP's national programme. This should alleviate some of the redundancies.
SRA says that TCS was doomed anyway because of the ‘impracticability of conducting future systems trials on the heavily used passenger and freight (West Coast) line and the need to develop an ERTMS train control system which also meets the broader aim of achieving capacity improvements'.
Under the new SNEP regime, testing of ERTMS equipment from ‘a number of firms in the European supply industry' will now be carried out at Old Dalby. With the demise of TCS, Level 2 System D is now the one true way forward.
It is also the toughest option, since it will mean the complete re-writing of the rule book to reflect a radical change in UK signalling principles. It also has some big unknowns.
David Waboso, now SRA Executive Director, Technical, who led the EPT hinted at one of these uncertainties when he said that SNEP would now concentrate its efforts on tests and trials including work to resolve the telecommunication issues ‘which remain a key technical challenge with ERTMS'. There is a box for the techie minded on this ‘challenge'.
He added that the UK development work would be ‘fully synchronised' with mainland European programmes and claimed that the UK now has the biggest ERTMS team in Europe .
In the SRA announcement on the formation of SNEP, further slippage in the West Coast Route Modernisation was revealed. The telecommunication masts and base stations already erected as part of the TCS contract will now be incorporated in the final ERTMS system ‘when it goes operational between 2010 – 2015'.
In the EPT Final Report a year ago, the ‘indicative industry plan (provisional)' showed that the WCML would be fitted with ERTMS by 2007. Now it is the first half of the next decade.
That, I think shows the scale of the technical challenge ERTMS represents. As has so often been the case, not least the Deltics, the temporary stop gap is now proving to be a long term solution. No wonder everyone is so keen on TPWS+.
Costing packetsERTMS Level 2 system D eliminates lineside signals. Instead, ‘signalling' information is transmitted to the train by radio and displayed in the cab. This is easily said but difficult to implement. GSM-R or the Global System for Mobile Communications – Railways is digital radio. The ‘C' is silent in the acronym, because GSM really stands for Groupe Spécial Mobile and it wouldn't do for the Americans to think it was a French concept.. As the billions paid by the mobile phone companies for their third generation GSM licenses showed, everybody wants a share of the radio frequency spectrum. After a lot of horse trading, the railways were allocated 876-880MHz and 921-925MHz for GSM-R. This represents 19 channels for the railways including a guard-band to prevent interference with adjacent channel. DataFor ERTMS Level 2/D it will have to transmit safety critical signalling equipment to trains running at up to 125mile/h. And if this information is not regularly updated, the train will be braked to a halt. Now you can transmit data over GSM-R in two ways – known as ‘circuit switched' and ‘packet switched'. With circuit switching, once the train's radio has made contact with the fixed network, constant capacity is provided irrespective of the actual demand. When an ERTMS equipped train enters a new area it will dial up the relevant Radio Block Centre (RBC) and be given a limit of movement authority expressed as a target speed. Remember that there are only 19 channels available. Remember, too, that GSM-R is designed for voice communication which calls for a continuous link with very short delays in end to end transmissions. With signalling data, such delays are less important. Three classes of service are defined for ERTMS, Class 1 requires a communications session to be established in less than 7 seconds with a probability of 99.9%. In contrast, Class 3 specifies less than 10 seconds with a 90% probability, 15 sec with 95% and 30 seconds with 99%. You can see that Class 1 is aimed at high speed lines while Class 3 would be fine for son of RETB on a lightly used route. Willesden or Windermere as it were. Then there is the issue of handing over between RBCs. For high speed running the on-train equipment needs to sign off from one RBC and set up a new session with the next quite quickly, typically under 5 seconds with a probability of over 99%. If this exchange doesn't happen, the ATP intervenes and the brakes come on. GPRSSo with only 19 channels and these constraints the original idea of running cab signalling with plain GSM-R is looking dubious. Enter a variant of GSM known as General Radio Packet Service or GPRS. In reality the data transmission requirements of ERTMS are not that demanding. The data ‘telegrams' sent to the train are short – typically between 50 and 250bytes. You need to send messages every few seconds and there may be a need for reception to be acknowledged in return. This is ideal for GPRS. In effect a number of trains are listening out on a common channel, instead of each tying up a channel. When a telegram with a train's unique address arrives the equipment on that train reads the telegram and displays the appropriate information in the cab. Even with the extra data needed for the protocols which ensure that the right message has been sent and received by the right train, packets will still be relatively small and the data rates relatively low. Another advantage is that that you can have seamless handover between adjacent areas, rather than closing one session and opening another. Note, too, that you could send non-vital data to and from the train simultaneously – such as customer information or fault data to the maintenance depot. So hurrah for GPRS then? Well, two cheers. For a start the ERTMS application implies a Class 1 maximum delay in data transfer of 0.5 seconds with a probability of 95%. The GPRS standard data transfer delay for 128 byte packets at this probability is less 1.5 seconds. True, GPRS has a ‘mean' delay of under 0.5 seconds but there isn't the equivalent of the ‘greater than 99% probability' required by railway signalling. Once again, the industry which everyone outside thinks so primitive and undemanding is really pushing the envelope. So, in the meantime Network Rail is installing GSM-R for voice only. But is seems likely that when ERTMS implementation starts GPRS will be added. |
What next for Saltley?In the original consultant's dream for the West Coast Main Line, moving block radio based signalling was linked to a single high-tech control centre for the route. Dubbed the Network Management Centre, it was renamed the West Coast Rail Traffic Control Centre (WCRTCC) when work on the builkding started at Saltley. Along the via dolorosa that is the West Coast Route Modernisation, WCRTCC was de-specced to cover only the southern end of the route. WCRTCC was intended to improve capacity and regulation using computer based decision making tools for routing services through congested junctions. Yes, yes, I know that Automatic Route Setting (ARS) in Integrated Electronic Control Centres (IECC) has been doing this sort of thing for ages, but they are old BR acronyms and the kit at Saltley is American. Also at WCRTCC would be the Radio Block Centre for TCS. This requirement is now anything up to 10 years away. As TCS slipped it became apparent that all the clever route setting kit at Saltley would be short of employment and the WCML without modern route setting aids. To fill this gap until TCS was ready around 2007, five ‘interim' control centres (ICC) for the WCML. These would be responsible for their local areas until control of the whole route passed to WCRTCC. As these were ‘interim', they would not be IECCs. Instead, the WCRTCC would be linked to the train describers and interlockings at the ICC. The decision tools would do their thang with this data and send the appropriate regulating strategy back to the ICC where it would be displayed on a screen for the edification of the signalmen. This hasn't happened either. Only two ICC have gone ahead – Wembley Main Line is operational and Stoke Box is being refurbished. And neither is linked to Saltley. So the WCRTCC hasn't much to do, apart from housing Midland Zone control. According to Informed Sources a consultants' report on the future for Saltley was commissioned as part of the ‘Baseline 4' project to redefine the WCRM upgrade. Not surprisingly is it reported to have concluded that the value of the WCRTCC has been seriously degraded by the changes in signalling policy. Meanwhile, AEA Technology Rail, heirs to those wonderful folk who brought you SSI and IECC haven't been waiting to see what happens next. Their associate European Rail Safety Applications (ERSA) of Strasbourg has developed an ERTMS/ETCS Traffic Simulator. This is a real time implementation of the various sub-systems which make up ERTMS Levels 2 and 3, including the Radio Block Centre, interlockings, regulation and the trains. Already humming away in a laboratory at Derby is an AEAT IECC controlling the ERSA ERTMS simulation running Level 2. So there's a thought – forward compatibility of IECC when ERTMS is (eventually) commissioned. Which raises the question of what to do with the big building at Saltley. My suggestion is to turn it into Network Rail's first tourist attraction - the West Coast Route Modernisation Experience. You could bring APT-P down from Carnforth, have animatronic tableaux of great moments in WCRM history. And as a final touch, you would buy a £2 voucher for tea and a bun on entry, only to find when you got to the cafeteria that the cost had risen to a tenner. |