Proceedings 2002/2003 - IRSE

SIGNALLING CONTROL CENTRES TODAY AND TOMORROW 59
Signalling
Control
System
Interlocking
Trackside
signalling
Minimum ETCS data flows
Additional ETCS data flows
Radio
Block
Centre
Trains
Figure 7: Interfaces – Interlocking, RBC and
Control Centre
ETCS simulator demonstrations typically show the
reported train position and length on a scale plan of
the track layout, but signaller’s workstation screens
do not attempt to show the railway to scale. A better
idea would be to associate the additional information
with the train describer berth in which the train’s
headcode appears. A small amount of additional
information could be provided continuously (eg
colour coding to show ETCS mode of the train), but
more detailed information would need to be shown
only when selected to avoid cluttering the workstation
screens.
INTEGRATING ADDITIONAL FACILITIES
PROVIDED AS PART OF ETCS
Most of the variable information required by the
RBC in an ETCS Level 2/3 system comes from the
interlocking or the trains, but there are functions
provided for in the existing ETCS specifications
which imply that there is a means of entering
additional information into the RBC. Of course, the
standards only specify the interoperable interface
with the train, so the source of this information is
undefined. For the ETCS trials being undertaken
around Europe, the RBC supplier generally provides
a terminal on which data can be entered. On the
Swiss Level 2 Pilot line, the signaller has access to
such a terminal. This shares a desk with his standard
workstation monitors, but there is no interface
between the systems.
It might seem obvious that the longer term
solution will be to integrate the additional RBC interface
into the signalling control system, but some
careful thought is needed to identify who is the user
of the facilities. For instance an important facility is
the entry of temporary speed limit information, but in
the UK at least this is not part of the signaller’s
duties. We need to first decide the rules and
responsibilities, and then engineer a system which
provides the people responsible with the facilities
they need. There have been a number of railway
projects where ambitious plans for fully integrated
control centres have not been delivered, and the
operators have found that separate systems for
clearly defined functions are indeed more workable.
Nevertheless it is likely that there will be facilities
which are best integrated – an example of this would
be the ETCS facility to send an emergency stop
message to an individual train. A non-integrated
system will provide facilities to stop a train by
replacing an individual signal or group of signals (or
“virtual signals”) to the stop state, but a facility for
the signaller to select this function directly for an
individual train would be a more intuitive response in
an emergency. This would also give a more rapid
system response as the command goes direct to the
RBC, instead of via the interlocking.
ADVANCED TRAFFIC MANAGEMENT FACILITIES
Signalling has traditionally provided the train driver
with the absolute minimum of information needed to
control the train safely. When approaching a point of
conflict where the train is going to have to be
delayed to allow priority to another train, the driver
only finds out when he sees the first caution signal.
At line speed, this is of course at the point where he
needs to start braking immediately. Up to that point
he may have been driving at the maximum permitted
speed to try to make up time, all to no avail as a
decision has already been taken in the control
centre to give priority to another train. If it was
possible to provide the driver with better advance
warning of train regulation decisions which will affect
the train, this could have a number of benefits:
• energy saving and reduced brake wear by
coasting or reduced speed running;
• fewer challenges to the train protection system,
as the driver is pre-warned that there is going to
be a requirement to stop;
• optimised route capacity at junctions and
bottlenecks, by avoiding stopping and starting
trains in the critical area;
• reduction in driver stress;
• improved passenger satisfaction, through better
provision of information about delays.
Traditional lineside signalling is not suitable for this
task, and whilst cab radio is now commonplace,
there is a policy (in the UK at least) that this should
not be used to communicate to a moving train
except in an emergency, to avoid distracting the
driver. It is interesting to note that in places where an
“open channel” radio system is in use, such as the
RETB radio signalling system, drivers appreciate the
access to information about other train movements.
ETCS Level 2 and above provides a communications
facility between the control centre and the
driver, via GSM-R radio and the Driver-Machine
Interface cab display (DMI). The information
displayed on the DMI is a big improvement on lineside
signals, as it includes all the speed limits as well
as the distance the train is authorised to proceed,
but it still fails to tell the driver anything about what
is happening beyond the current limit of movement
authority. However, there is no reason why the DMI
should be limited in this way, and the DMI concept
which has evolved with ETCS includes fields for