Train coupler, system and method for automatic coupling trains, and related train

A train coupler comprising:

• a mechanical coupler configured to couple with another train coupler;
• a primary pneumatic circuit comprising a main air distribution line adapted to be connected with and supply air into a pneumatic circuit of said another train coupler, via a first inlet/outlet;
• a movable electrical head connected to a first actuator which is configured to be pneumatically actuated and drive the electrical head to move between a non-operative retracted position and an extended position where it is adapted to be electrically coupled with an electrical head of said another train coupler;
• a secondary pneumatic circuit which is pneumatically connected to said primary pneumatic circuit and is arranged to convey flows of air derived from said main air distribution line towards said first actuator and a second inlet/outlet, the second pneumatic circuit being configured to be pneumatically connected with the pneumatic circuit of said another train coupler via the second inlet/outlet, wherein said secondary pneumatic circuit is configured to be switched, based on an electrical activation signal generated by a train controller, between a first operative configuration where the derived flows of air towards said first actuator and said second inlet/outlet are blocked, and a second operative configuration where said derived flows of air are permitted pneumatically actuating at least said first actuator to drive the electrical head to move to the extended position for electrically coupling with the electrical head of said another train coupler.