ERTMS Level 1 is a Train Control System based on track-to-train
communication by an intermittent system. Its main features are:
- Possible Overlay to a pre-existing signalling system
- Movement Authorities and position reference through Eurobalise®.
- Train Integrity & Position by Track Circuit.
Components and functions of the Wayside equipment:
LEU:- Captures movement authority information from interlocking or signal
aspect
- Selects and sends telegrams to Eurobalise that contain movement authorities
and trackside data
Eurobalise®:- Stores infrastructure data as pre-formatted ‘telegrams’ (position
reference, speed limits, line gradient, works on the line, etc.)
- Is energised by power from train antenna
- When energised sends to train movement authorities and trackside data
(telegrams selected by LEU)
Radio In-Fill:
Radio In-fill is a function that can be optionally added to ERTMS Level 1 in
order to increase the performance of the line. The purpose of the Radio Infill
Unit is to transmit the message corresponding to a Eurobalise in advance of the
train. In this way, a train approaching the application zone of a more
restrictive condition can revoke braking as soon as the ‘signal clears’ without
waiting to reach the balise itself. The infill message is transmitted via radio
using GSM-R and Euroradio safety protocols, as used in ERTMS Level 2. The use
of radio allows continuous infill coverage for data radio equipped trains on
fitted sections between balises.
Mainfunctions of On-Board equipment:- Receipt and analysis of the information about trackside status and
characteristics of the movement authority sent by Eurbalise or by the Radio
Infill Unit
- Calculation of the speed profile in relation to the train characteristics
which are already stored on-board
- Selection of the most restrictive speed value to be observed at the
locations ahead
- Comparison between the train’s actual speed with the permitted speed and,
if necessary, automatic brake application
- Display of indications and provision of alerts / warnings to the
driver
