Information Technology Reference
In-Depth Information
- it does not allow sectional release in the signal boxes (systematically used
in France for example). Each switch has consequently its own track circuit
and can been released and moved immediately after the train movement
3
;
- it requires the train controller to apply special procedures in case of
malfunc-tion, including on open track (resetting and verification that the
track sections are clear of all trac). This means that the information
train controllers need to follow those procedures;
- it does not allow fulfilling some of the national signalling functions on the
French network, such as continuous train warning at level crossings . . .
Accordingly, the TC's replacement by ACs, keeping all else constant,
would inevitably lead to hazardous situations.
From the standpoint of infrastructure management and maintenance, It
is necessary to consider specific constraints brought by the TC, in particular
that:
- circuit of the traction return current has to be ensured compatibly with
the TC functioning and the track insulation;
- track insulation has to be guaranteed (typically minimal guarantied value
from 2,5 to 8
Ω
.km in France);
- insulation
4
joints has to be maintained in relation with the trac load;
- rolling stock has to fulfil some “EMC requirements”, in particular regard-
ing the traction return current . . .
It is necessary to consider specific constraints brought by the AC, in
particular that:
- it seems less simple to maintain, whereas it makes it necessary for mainte-
nance workers to follow special procedures, drawing on railway resources,
since AC failures often require manual resetting (no equivalent in TC);
- rolling stock has to guaranty some “EMC requirements”, in particular
regarding the electromagnetic field generated in direction of the detectors;
- the track checking periodicities have to be adapted to reduce the risk and
the possible consequences of a BR;
- the track grinding periodicities
5
have to be adapted to reduce the risk and
the possible consequences of a broken rail (preventive grinding 3 times a
year ...).
3
In France, a switch can authorize a new train for another direction 5s after the
TC release
4
In France, around 50% of the track circuits are jointless and this part is growing.
5
It comes from the RIL 821 that: Rail wear during visual track supervision -
visual (2 months); Internal Rail Integrity - Rail stability, rail cracks, rail welding
stability, surface damage (4 months at 80km/h) and Rail Head Condition - (12
Months at 90km/h). In France, the periodicities of the internal rail integrity
checking are divided by two if the track isn't equipped with track circuits.
