Grüntal junction
![Schematischer Plan Gruental Crottendorf Schwarzburg](https://tu-dresden.de/bu/verkehr/ibv/ebl/ressourcen/bilder/shematischer-Plan-Gruental-Crottendorf-Schwarzburg.PNG/@@images/19a86a20-9c2c-4204-8d9f-80f1f22882df.png)
Schematic track diagram
At the Grüntal junction, the line from Crottendorf (staging yard) joins the single-track line Adorf - Feldberg - Grüntal - Dornbach - Zellwald.
![Gleisanlage Grüntal](https://tu-dresden.de/bu/verkehr/ibv/ebl/ressourcen/bilder/zug-gruental.jpeg/@@images/d03b7da7-6a45-4a82-8b53-367766d92cf4.jpeg)
Grüntal with stop and panels for Crottendorf and Schwarzburg in the background
A mechanical interlocking with key mechanism, block top and signal levers as well as a track diagram interlocking type GS II are available as operating stations.
The switch is reproduced as a locally operated, key-dependent switch. The keys match the switch locks of the switch in the outdoor layouts.
The protection switch on the layout allows the reproduction of an alternative connection point.
![Stellwerk Grüntal](https://tu-dresden.de/bu/verkehr/ibv/ebl/ressourcen/bilder/stw-gruental.jpeg/@@images/743f4a9a-d165-4f9a-9d05-dea5afaef184.jpeg)
Key interlocking with signal levers in Grüntal
Main contents to be learned
- Operating a mechanical interlocking by means of a key-operated system
- Offering/accepting on single-track lines
- Coordination with the 3 neighbouring operating centres is absolutely necessary as all incoming lines are single-tracked.