Modern public transit is under dual pressure: meeting strict passenger safety requirements under EN 50122-1 while protecting city infrastructure from the destructive effects of stray currents. Voltage Limiting Devices (VLD) from SALTEK offer a clear solution to this engineering paradox. More than just a safety device, they’re an active asset management tool.

Key Benefits:

1. Protection Against Dangerous Touch Voltage (Safety Compliance)

In DC traction systems, electrical potential can build up on the rails, sometimes exceeding safe touch-voltage limits. Without protection, this potential can be conducted to metal platform elements, such as overhead structures or railings, thereby putting passengers at risk. Acting as an invisible guardian, SALTEK VLDs detect voltage spikes in milliseconds and immediately bring the potential down to a safe level. With SALTEK VLDs, even the strictest European safety standards can be met without compromise.



2. Safeguarding Utility Networks Against Corrosion (Asset Protection)

This is an often overlooked benefit that happens to deliver the biggest savings. When rails are permanently grounded, stray currents become a source of electrochemical corrosion, affecting nearby gas pipelines, water mains, and bridge structures. SALTEK VLDs keep the system electrically isolated, grounding it only when safety demands it. With advanced forced switch-off technology, they reduce stray current leakage and extend the service life of urban infrastructure by decades.



3. Three Functions in a Single Device

Say goodbye to complicated assemblies of switchgear components. The BVL series integrates:

  • VLD-O for normal operation (thyristors),
  • VLD-F for emergency and fault conditions,
  • and a high-performance surge protective device (SPD) for lightning protection.
  • The result is a compact set-up with minimal interconnection impedance, maximizing protection efficiency.

4. Predictive Maintenance and Smart City Integration

VLDs are no longer a “black box.” With support for communication protocols and integration into SCADA systems, SALTEK VLDs provide valuable data on a track’s condition. Noticing an increase in switching cycles? This may indicate a deterioration of the track or its components. Address issues early on, before they disrupt operations.



Don’t wait for corrosion to rack up the costs or for a failure to halt operations. Contact our specialists today. We’ll design a solution that pays for itself by extending your network’s service life.

Contact our Business Development Manager - Pascal Magon  p.magon@saltek.cz

You can also view our product catalog here or explore our full range of products here.