The article describes the challenges to ERTMS in Europe

1. euRope | signalling
Tackling the challenges to
standard train control
ETCs Some decisive action needs to be taken soon in order to ensure the evolution of a truly
standardised european Train Control System.
Frank Walenberg, Rob te Pas and
lieuwe Zigterman*
O
bservers of the European
railway scene could be
forgiven for thinking
that there is something
seriously wrong, as operators and
the supply industry struggle to adopt
the European Rail Traffic Manage-
ment System. Progress is slow, and it
is clear that implementation of ETCS
is taking place in small steps.
Some progress has been made
towards interoperability. The legal
framework is in place, and the insti-
tutions are largely established both
in the member states and at the Eu-
ropean level. The first interoperable
lines have been put into operation,
and traffic is starting to grow. This
should pave the way for interoper-
ability to move from ‘pragmatic’ to the systems operational. So today, A DB Class 189
‘full’ implementation. But whilst the we have a ‘consolidated’ version locomotive
undertaking
end vision is clear, it seems that not and something referred to as 2.2.2 ETCS tests at
enough attention has been paid to ‘Corridor’. It is clear that the differ- the Wegberg-
Photos: DB Schenker
common international migration ent suppliers, who are all members Wildenrath
circuit.
strategies, and the interoperabil- of Unisig, have been implement-
ity issues that arise when railways ing slightly different functionalities
have reached different stages of based on identical specifications.
implementation. To try and make sense of the
ETCS Level 2 is now in com- confusion, the European Railway to implement this by updating the
mercial operation in Switzerland, Agency, as designated System Au- equipment and software on existing
Italy, the Netherlands and Spain, thority for ETCS, published a new rolling stock and infrastructure.
amongst others, and many more SRS Version 2.3.0 on March 7 2007. Meanwhile, ERA is working to-
railways have Level 1 installations However, it became evident that this wards Version 3.0.0, which will in-
to a greater or lesser degree. Most of was incomplete, so a debugged ver- clude functional updates requested
these are based on System Require- sion (2.3.0D) was officially adopted by many different parties. For exam-
ments Specification Version 2.2.2, on May 24 2008. Suppliers and infra- ple, RFI of Italy is asking for radio
but with local modifications to get structure managers are now trying infill and SBB wants Level 1 with
Limited Supervision. The indus-
* Frank Walenberg is Director of KeMA Rail Transport Certification, where
try’s current expectation is that the
Rob te Pas is principal Consultant and lieuwe Zigterman is Senior Assessor. Version 3.0.0 specifications will be
signed off by December 2012, and
that the suppliers will have their
products tested and approved three
years later. This would allow for op-
eration using 3.0.0 to start in 2016.
Putting this in a positive light, the
ETCS community is in the throes of
a learning process to settle specifica-
tions that can guarantee unified, and
hence compatible, implementation.
Railway Gazette International | March 2009 33

2. signalling | euRope
conditions, but only after one or
more ‘abnormal’ events.
system integration
When a new line or an upgraded
route is taken into service, many con-
ditions have to be met. It is not suffi-
cient simply to equip track and trains
with ETCS and GSM-R, the two main
components of Ertms. This is because
the infrastructure consists of numer-
ous subsystems such as bridges and
tunnels, power supply and stations,
while there are countless different
types of rolling stock. Operational
procedures are markedly different
too.
Fig 1 illustrates how the different
TSIs apply to the railway and its sub-
systems. The upper half of the diagram
concerns Conformity Assessment at
the subsystems level as determined in
interoperability legislation. Note that
significant elements of the operating
This Vossloh But the learning process is continu- which is the permitted speed limit in railway are not covered by TSIs, for
G1206 operated ous, and the railway sector may not ‘unfitted’ mode where the on-board example interlockings and train de-
by Dutch open-
access company be well equipped to manage it. equipment is not working. This was tection systems.
ACTS is equipped seen as a failure mode that would Each TSI still has an Annex which
with ETCS Level
Ertms in practice only occur on rare occasions. In one lists a number of ‘Open Points’. In
2 for use on the
Betuwe Route.
sample country the permitted speed relation to Ertms, Annex G of Com-
Concerned by the various national is 10 km/h, but one of its neighbours mission Decision 2006/860/EC men-
differences in Ertms implementa- allows 100 km/h, another 160 km/h. tions (amongst many other items) the
tion, in 2007 ERA commissioned Each country claims its choice is following:
KEMA Rail Transport Certification based on sound arguments, but it • requirements for reliability and
to undertake a study of experience would be hard to explain to a driver availability;
with implementing Ertms, with a why such important changes oc- • requirements for safety and safety
particular focus on safety approval cur when his train crosses a border. analysis;
procedures. This study was con- In most cases these differences will • odometry functional interface
ducted in co-operation with RINA only become apparent to the driver specification;
(Italy), Cetren (Spain) and Attica under specific failure conditions, • version management.
Advies (Netherlands). which makes the issue potentially For the time being, the TSI requires
One of the most important find- quite serious. Most railway accidents each member state to define its own
ings was that system integration is do not happen in normal operating requirements in these areas. In theory,
not well covered by the European
regulations. This is the responsibility
of individual member states, and as
a result, many national procedures TSI TSI (Notional, TSI TSI TSI
Regulatory technical
Non-
remain in place. OPE CCS open points) ENE RST INF
Step 1. Conformity
TSI
That is bad enough, but there is parts
worse. As agreement could not be
assessment
conditions
reached on all aspects of ETCS, the Onboard
assembly
Trackside
assembly
key players invented National Values
to identify parameters where coun-
tries may (and do) choose different
standards.
A good example is ‘V_nvunfit’, CCS integration
Operational
Step 2. Putting
conditions
into service
System integration
Technical specifications for
interoperability Putting into service
ope = Traffic operational & Management;
CCS = Control, Command & Signalling
eNe = energy; Fig 1. How the TSIs apply to the railway and its subsystems. The upper half of the
RST = Rolling Stock; diagram concerns Conformity Assessment at the subsystems level as determined in
INF = Infrastructure European legislation on interoperability, and the lower half shows the steps required
when a railway enters service.
34 Railway Gazette International | March 2009

3. euRope | signalling
these national requirements should HSL-Zuid between Belgium and the function correctly in each country,
be exchanged at European level, and Netherlands. even when operating in degraded
at some point in the future, the EU The TSI assumes that each Class mode. In a typical example, the sys-
hopes this may lead to a consensus. B system is controlled via a Specific tems for countries X and Y are put
The lower half of Fig 1 shows the Transmission Module. The Unisig into ‘sleeping mode’ when the train
steps required when a railway is taken Subsets in Versions 2.2.2 and 2.3.0 dis- is running in country Z. The systems
into operation. The first is to integrate tinguish between an STM-European needed in countries X or Y are woken
the lineside and onboard equipment and an STM-National. The former is up by an ‘activation event’ which oc-
(CCS integration). Integration of all the ideal from the point of view of in- curs as the train enters that country.
other subsystems then follows, with tegration, as it only handles the track But the ETCS designers have as-
a period of trial operation before the interface, while all logic processing sumed that the whole European net-
line can enter commercial service. for multiple STMs would be concen- work is being equipped with ETCS,
The study showed that each mem- trated in the on-board European Vi- or at least with transition balises
ber state goes about implementation tal Computer. An STM-National, by at each border crossing. Thus the
in its own way. There are no common contrast, more or less maintains the Class B systems for countries X and
rules for the period of trial running. existing ATP system, which is simply Y, which are not active in country Z,
No common criteria are defined to switched on or off by the EVC. are not put in sleeping mode but are
specify when a new line can be put So far only a limited number of simply switched off. They would then
into service, and there is no common STM-N modules have been devel- be switched on again by a transition
approach to safety testing. oped, and we do not know of any balise.
There also are significant varia- STM-E. There are even suggestions Yet in reality transition balises have
tions in the way that safety approvals that the provision for STM-E could not yet been fitted at all relevant bor-
are handled compared with what is be removed from the Version 3.0.0 ders. If a train re-enters country X
required in the certification process specifications.
for interoperability. In some cases as- At present, there is no provision
sessment by the Independent Safety for co-ordination between different
Assessor is seen as part of the interop- STM-Ns. A specific example high-
erability certification, while in others lights what may happen. When op-
a separate ISA assessment is given the erating on a Class B system, the CCS
highest priority before a line enters TSI defines which STM should be
commercial service, and interoper- used. As defined in Annex A of both
ability is left until later. the High Speed and Conventional
In either case there is little experi- TSIs, the ETCS kernel determines the
ence of assessment for international level of safety provided, either ETCS
cross-acceptance. Apart from deci- or ‘Level-STM’.
sions by Notified Bodies about ISA Starting a train from cold, a driver
acceptance, the legislative ground for must input the appropriate level. Se-
safety cross-acceptance is weakened lecting ‘Level-STM’ brings up a list of
by different views about assessors’ available STMs on the DMI, and the
qualifications and liability. driver can then choose the correct at such a border, the Class B system A Euroantenna
Looking at operations, current system. However, it is possible to se- remains switched off. This border fixed to the
underside of
practice is that bilateral agreements lect the wrong one. For example, on would still be equipped with the ‘old’ the train for
are negotiated between infrastruc- a Thalys train in the Netherlands, a activation code for a sleeping Class B communication
ture managers and railway undertak- driver could select the STM for Bel- system, but this would not be ‘heard’ with balises.
ings as well as between infrastructure gium, which would mean that the sys- by a train running with the system
managers in neighbouring coun- tem would operate to TBL1 specifica- switched off. Once again, there is a
tries. But these agreements are not tions, as a warning system rather than risk that the level of safety could fall
standardised. a train protection system. The driver as a result of STMs being controlled
would expect the Dutch ATB to pro- by ETCS.
Multiple Class B systems tect his train, reducing the speed to We are concerned that the speci-
40 km/h if no ATB signal is received. fications do not consider the prob-
The CCS TSI distinguishes between However, STM TBL1 only introduces lem of transitions between existing
the Class A system (ETCS), and Class emergency braking if train speed ex- national systems in sufficient detail.
B national train protection systems. ceeds 160 km/h, and the train protec- Chapter 4 of Subset 026 includes the
Rolling stock for international serv- tion system in the Netherlands would ETCS Transition Table for all ETCS
ices is usually equipped with several not function until an ETCS balise was modes, including STM-E and STM-
Class B systems to run in different passed, which would reset the system. N, but there are no transitions from
countries. For example, a Thalys So in some circumstances the intro- one STM mode to another: transi-
PBA trainset is fitted with the French duction of ETCS, and particularly the tions SESE and SNSN have been
KVB and TVM, the Belgian TBL and control of STMs by ETCS, may actu- omitted!
Crocodile, as well as the old and new ally reduce the level of safety. Our experience suggests that inter-
versions of the Dutch ATB. The PBKA national freight traffic, on Corridor
trainsets also have PZB/LZB inductive Border transitions A between Rotterdam and Genova
train control to operate in Germany. for example, is already encountering
Thalys trains are now being fitted with When trains cross several borders, such transition problems. And with
ETCS Level 2 so that they can run on it is clearly important for the ATP to the profusion of traction leasing,
Railway Gazette International | March 2009 35

4. signalling | euRope
infrastructure manager, whose choice is needed to reduce this tendency.
of trackside equipment is influenced Harmonisation of the European
by the characteristics of the rolling railway network is clearly a long-
stock using the routes being fitted. term task, because of the enormous
To date there is no agreement costs involved. Interoperability is
on braking curves in the TSIs. The not a goal in itself, but is intended
Ertms User Group has taken the lead to create the conditions for an open
in the search for agreement on a com- railway market. Nor does it solve the
mon braking model, and while this financial problems of further intro-
process is well in hand, agreement on duction and implementation of in-
braking curves in the TSIs must await teroperable technologies. The next
the issue of Version 3.0.0. Yet while steps towards creating a true mar-
agreement on a common braking ket largely depend on the political
model may be within reach, there is will to define and support effective
no sign of an agreement on the pa- migration strategies. Future success
The cab of an locomotives are likely to be used in rameters to be used in the model. will also depend on feedback from
ETCS-equipped many countries, meaning that doz- Meanwhile, each operator or roll- experience, the ability to monitor
Vossloh G2000
locomotive. ens of transitions between Class B ing stock manufacturer has to decide and measure progress with interop-
systems will have to be taken into which braking curves to apply, and erability, and to recognise the rea-
account. the Notified Body then has to assess sons for any lack of progress.
the choices made. In our experience, We believe that some decisions
Operators affected the braking curves adopted in recent need to be taken urgently to progress
years are often ultra-conservative — the evolution of Ertms. To that
Infrastructure managers acting every party seems to want to increase end, we would like to offer some
only within their own country prefer the safety margin. This leads to brak- suggestions:
to install balises which command and ing curves which lengthen headways • allow a ‘sleeping’ mode for Class B
accept only those systems that apply significantly. In extreme cases, the al- systems:
in that country. For example, the on- lowable braking distance for a freight • agree on the inclusion of ‘foreign’
board equipment on a train entering train running at 100 km/h can be as Class B systems in the ‘priority lists’
the Netherlands will be instructed much as 2 km. for transition packages;
by a balise to switch to ATB, and no • explicitly address the need for
alternative is permitted. When ap- The way ahead SESE and SNSN transitions,
proaching either the Betuwe Route or to accommodate border crossings
HSL-Zuid, the train will receive Level Ertms is not the only driver of between STM operations in differ-
2 commands, with Level 1 as a fall- interoperability, but is perhaps the ent countries;
back on HSL-Zuid. most important, and the most visible • eliminate National Values, or agree
As a consequence, if the ETCS fails, sign of progress. The gradual devel- a smaller range for different speed
and is not able to switch to Level 0, opment of a global market for ETCS values;
the driver must isolate the equipment also offers an important incentive for • continue working to establish com-
by breaking seals. Depending on his European suppliers to improve their mon braking parameters.
actions, he might then be permit- competitiveness. We have learned that the path to-
ted to continue the trip with no ac- The separation of responsibility for wards an interoperable European rail-
tive train protection. If the transition infrastructure management and train way is long and arduous, and much
balises on the approach to the Betuwe operations is a cornerstone of Eu- still lies ahead of us. We can choose to
Route also allowed for ATB (as a sec- ropean railway policy, aimed at im- return to the multi-national route of
ondary option in the priority list), the proving the attractiveness and com- the past or we can choose a route that
system might switch to ATB, which petitiveness of the rail sector. But as leads to a true European railway. So
would provide a degree of protection a consequence of this approach, the much effort has already been put into
by limiting train speed to a maximum new concepts of interoperability, TSIs the introduction of Ertms, and this
of 40 km/h. and certification are essential to re- progress should not be put at risk.
The consequences of choices made store a systems structure. Strict appli- The decision time is now. l
by infrastructure managers will af- cation of these instruments is needed
fect train operators, especially freight to reach a stable structure. In par- glossary of Ertms
companies, all across Europe. As ticular, TSI-OPE needs to be applied
terminology
these companies operate in a genu- more strictly. And it is important to
inely competitive market, they do not recognise that the interoperability of Ertms = european Rail Traffic Manage-
spend time discussing Ertms and all subsystems can only really be dem- ment System
eTCS = european Train Control System
its complications. They simply want onstrated through certification.
FRS = Functional Requirements
to run their trains. Confusion about the definition Specification
of interoperability and other issues STM = Specific Transmission Module
Braking curve parameters seem to be making the application DMI = Driver Machine Interface
of TSIs difficult, creating openings SRS = System Requirements
Another key issue is the question for some countries to continue their Specification
eRA = european Railway Agency
of braking parameters. This involves national approaches. Further devel-
Unisig = Consortium of principal eTCS
the ETCS equipment manufacturer, opment of the TSIs, to improve their signalling suppliers
the rolling stock supplier and the completeness and ease of application,
36 Railway Gazette International | March 2009