MD EQUIPOS TENOLÓGICOS is specialized in the design and manufacture railway protective devices. Many of the protective devices developed in our company are the result of different engineering companies and railway administrations collaboration to resolve specific problems.


All MD devices are designed under robustness and highest reability criteria.


Since every protective device is designed and developed by MD, it is possible to satisfy each of the client’s needs or requirements by developing customized devices.

Among the designed and developed devices it is worth to stress:


VLD-F protective devices.


Polarized protective devices (DPPo / VTD).

Interval discharger devices.

Electrolytic corrosion protective devices.


VLD-O protective devices.


Rail-to-earth voltage limiting device.



Overvoltage protection of substation rectifier groups.


Overvoltage and MF/AF harmonics protection


Electrical-electronic equipment of auxiliary services.


Protection of interlocking cabins.


Overvoltage protection of signaling circuits.


Protection against current peaks.


Protection of Medium and High Voltage shields.


Indoor autovalves with remote signalling.