Setting up an AC single rail track circuit requires a specific procedure because one rail remains continuous while the other rail is insulated to define the track block.
The first step is to identify and insulate only one running rail at the boundaries of the desired track block using insulated rail joints. The other rail remains continuous and electrically connected through the block.
The AC power source, usually a transformer, is connected between the insulated rail and the continuous rail at one end of the track block. Connections must be secure and compatible with the design voltage and frequency.
The AC receiver, relay, or electronic detection unit is connected between the same insulated rail and continuous rail at the opposite end of the block. The receiver must match the operating frequency and voltage of the power source.
In a basic AC single rail track circuit, impedance bonds are generally not required at the insulated joints because the continuous rail provides the return path for current.
After installation, thorough testing and calibration are required. This includes applying a shunt between the insulated rail and the continuous rail at different points in the block and verifying that the receiver properly detects occupancy.
Voltage and current readings at the receiver should be checked against specified limits to confirm reliable operation.