On electrified lines there is high voltage above every track. Anyone building there needs defined switching states, and the switching applicant is the function that applies for and coordinates them.
Why a switching application is needed
The overhead line of electrified lines carries high voltage, in Germany 15 kilovolts. Work in its danger zone is only permitted if the affected section is switched off, earthed and short-circuited. The switching application is the procedure by which this safe state is requested from the operator and established.
Without the defined switching state, life-threatening electrical accidents are a risk, and not only on contact: even approaching an overhead line that is still live can be fatal through an arc. That is why the function is tightly regulated and bound to authorisations.
This affects not only obvious work on the overhead line itself, but also activities with cranes, lifting gear or long components nearby, where the safe distance cannot be reliably maintained.
The role of the switching applicant
The switching applicant applies for the required switching states, coordinates them in time with the construction process and ensures that work only begins once the safe state has been confirmed. They form the interface between the construction site and the operator’s switching control, and are responsible for ensuring that the requested section matches exactly the area being worked on.
In practice this function interlocks closely with the Technischer Berechtigter, who is responsible on site for protection against hazards from electric current. When both authorisations lie in one hand, a critical interface is removed and the coordination between application, release and the actual start of work becomes more reliable.
Time windows and delay
A switching state never applies indefinitely, but for an agreed time window closely coordinated with the operational schedule. When the window ends, the line is switched back on, regardless of construction progress. Delays on site must therefore be reported to the switching control immediately so that the window can be extended or reapplied for.
The course of a switching operation
What makes up the safe state
A switched-off section is not yet automatically safe. The safe state only arises from the interplay of several steps carried out in a fixed sequence:
- Disconnect: the section is isolated from the voltage on all sides.
- Secure against re-energising: accidental switching back on is ruled out.
- Verify the absence of voltage: it is checked that no voltage is actually present any more.
- Earth and short-circuit: the section is earthed and short-circuited so that any induced voltage also drains safely.
Only once this state has been established and confirmed is the work area released. The earthing remains in place throughout the entire work and is only removed after it is completed.
Häufige Fragen
What is a switching application on the railway?
A procedure by which the switching off, earthing and short-circuiting of an overhead-line section is requested from the operator so that work can be carried out there safely.
Who may submit a switching application?
A suitably authorised person, the switching applicant. In practice this function is often combined with that of the Technischer Berechtigter.
Why is switching off alone not enough?
Only switching off, earthing and short-circuiting establish the safe state. Merely approaching an overhead line that is still live can be fatal.
Edoé Lassey
Edoé Lassey führt die LND Ingenieure GmbH als Bauüberwacher und Ingenieur für Infrastruktur- und Tiefbau. Die zertifizierten Rollen Technischer Berechtigter, Sicherungsüberwacher, Schaltantragsteller und Bauvorlageberechtigung gehören zum Leistungskern.
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