A railway beacon having a casing (3) supporting an electronic circuit (4), which receives an electromagnetic enabling signal from a vehicle travelling along a railway line, and generates a coded response signal (telegram) transmitted to the vehicle. The casing (3) is formed in one piece from insulating material, and has at least one sunken seat (12a) housing the electronic circuit (4), which is embedded in a layer of insulating silicone resin (40) poured and set inside the sunken seat.