Combined track balise

Small combined track balise 1000 / 2000 Hz

Small track balise GFSU PB 21 is used to transfer information from the rail to the train, inductively based on resonant currents. The purpose of a balise is to initiate logical process in autostop device, which can follow three directions:

  • Warning to the driver to reduce the speed of the train
  • Stopping of train with braking, if the driver doesn’t follow the procedure
  • Rapid unconditional braking if the train for whatever reason passes by the red signal

Locomotive part of autostop device produces alternating magnetic field of tree frequencies, 500,1000, 2000 Hz. When LPG comes over active indusi balise, of which passive oscillatory circuit has its own frequency similar to one of produced frequencies of LPG, there is a mutual inductive influence between LPG and indusi balise. Final result is reducing of resonant current in LPG and of that frequency that has active indusi balise. Decrease in resonant current is processed in logical units of AS to the level of executive command. This tree-frequent resonant technique uses frequencies on the principle:

  • Influence of 2000 Hz circuit immediately and unconditionally leads to braking
  • Influence of 1000 Hz circuit controls driver’s vigilance and speed control after certain time period


Housing cast in AlSi12 and annealed in order to get corresponding magnetic characteristics. Cover which closes upper side of indusi balise made of polyester reinforced with glass fiber and has high softening and melting point. Ferrite core of rectangular diameter placed into housing of rectangular diameter is made of component glass mass. For fixing it is placed on non-magnetic pole and tighten with non-magnetic nuts, and then glued with special glue for protection of moisture and increasing of mechanical firmness. Coil is made of wire based on thermodure. Hole unit is locked on the inside of the housing which is filled with purr foam. Condensers of high demands and small dimensions are placed in separate chamber of housing which is closed with cover with the rubber sealing.

Frequency setting area: 1000 Hz 1008-1012 Hz
2000 Hz 2008-2016 Hz
Electricity reduction value: 1000 Hz 0 - 27 mA
2000 Hz 0 - 27 mA
Q factor value: 1000 Hz Q >= 12 with cable
2000 Hz Q >= 24 with cable
Value of insulation resistance 500V: >= 50 M
Dieletrice firmness: 2500 V 50 Hz
Temperature area: -40 °C   do   +85 °C
Protection type: IP 67
Environment influence: ITC 60721
Dimensions (length x height x width): 644 x 130 x 300 mm
Weight: 15 kg