Technology Think Tank

What is Insulation Intrusion Limit

Intrusion insulation, also known as overrun insulation, is the track insulation section behind the turnout. In order to prevent the side line conflict, the insulation joint should be set at 3.5~4m away from the warning mark. However, due to the limitation of conditions, the installed insulation joint is less than 3.5m away from the warning mark. This kind of insulation is called invasion limit insulation.Specifically, when the rear wheel of the vehicle just crossed the intrusion limit insulation and stopped inside the insulation joint, although the rear track circuit had been unlocked, in fact, because the rear wheel of the vehicle was still less than 3.5 meters away from the rear end of the vehicle, although the light band at the rear of the train had disappeared and passed the mark on the console, the rear coupler or the end of the vehicle body might still invade the limit of the adjacent line, it will affect the safety of the adjacent line.

  1. On two adjacent track circuit sections with intrusion limit insulation, it is strictly prohibited to park rolling stock (except for the track circuit section of the departure line).
  2. When a track circuit section on the road (hereinafter referred toWhen "this section") and its adjacent track circuit section (hereinafter referred to as adjacent section) are provided with intrusion limit insulation, the switch position and occupation of the adjacent section must be confirmed through the console (or display screen) before arranging the access road.
  3. When the adjacent section is occupied (red light band is displayed) and this section cannot form parallel access roads, it is strictly forbidden to use this section to arrange related access roads.
  4. In case of construction or track circuit failure, poor shunt, etc. in adjacent sections, the confirmation of adjacent sections must be confirmed by competent personnel on site and reported to the station attendant.
  5. When construction is carried out in the section with invasion limit insulation, the station must carefully check the scope of influence according to relevant technical data to prevent wrong determination of the scope of influence.
  6. For stations with intrusion insulation, carefully check the operation requirements included in the relevant provisions of the "Station details" with those provided by the electrical department.Whether the "instructions for use" are consistent. Meanwhile, measures to ensure operation safety shall be formulated according to relevant requirements.