A bogie and a monitoring system for acquiring, processing and transmitting operating data of the bogie, wherein the bogie comprises: - a bogie frame which supports at least one railway axle, - at least one axle box arranged at one end portion of the railway axle; - at least one covering device of the axle box attached to the axle box and adapted to define a respective inner compartment between the axle box and the covering device; wherein the monitoring system comprises: - at least one sensor node (20a, 20b), associated with the axle box and comprising at least one sensor (21, 22) positioned in the inner compartment, adapted and configured to acquire operating data of the axle box; characterized in that: the monitoring system comprises a concentrator node attached to the bogie frame outside the covering device of the axle box, the concentrator node being operatively connected to the sensor node (20a, 20b) by means of a wired connection line to receive said acquired data, wherein the concentrator node comprises at least one local processing unit, adapted to process the acquired data and obtain processed data, and a radio communication interface (54, 55) for transmitting said processed data outside the concentrator node, wherein said at least one sensor node (20a, 20b) comprises an electric generator adapted to produce electrical power by converting part of the rotational kinetic energy of the axle, and wherein the electrical power produced by the electric generator is used to feed the processing unit and the radio communication interface (54, 55) of the concentrator node, wherein the electrical power is transferred by the sensor node (20a, 20b) to the concentrator node by means of the wired connection line; - the bogie frame comprises a lower face, facing the ground in a normal use condition of the bogie, and an opposite upper face, and wherein the concentrator node is housed in a container attached to the lower face of the bogie frame; - the communication interface comprises a pair of directional Wi-Fi antennas reciprocally oriented in opposite directions along, or parallel to, a driving axis of the bogie. - a bogie frame which supports at least one railway axle, - at least one axle box arranged at one end portion of the railway axle; - at least one covering device of the axle box attached to the axle box and adapted to define a respective inner compartment between the axle box and the covering device; - at least one sensor node (20a, 20b), associated with the axle box and comprising at least one sensor (21, 22) positioned in the inner compartment, adapted and configured to acquire operating data of the axle box; the monitoring system comprises a concentrator node attached to the bogie frame outside the covering device of the axle box, the concentrator node being operatively connected to the sensor node (20a, 20b) by means of a wired connection line to receive said acquired data, wherein the concentrator node comprises at least one local processing unit, adapted to process the acquired data and obtain processed data, and a radio communication interface (54, 55) for transmitting said processed data outside the concentrator node, wherein said at least one sensor node (20a, 20b) comprises an electric generator adapted to produce electrical power by converting part of the rotational kinetic energy of the axle, and wherein the electrical power produced by the electric generator is used to feed the processing unit and the radio communication interface (54, 55) of the concentrator node, wherein the electrical power is transferred by the sensor node (20a, 20b) to the concentrator node by means of the wired connection line; - the bogie frame comprises a lower face, facing the ground in a normal use condition of the bogie, and an opposite upper face, and wherein the concentrator node is housed in a container attached to the lower face of the bogie frame; - the communication interface comprises a pair of directional Wi-Fi antennas reciprocally oriented in opposite directions along, or parallel to, a driving axis of the bogie. - the bogie frame comprises a lower face, facing the ground in a normal use condition of the bogie, and an opposite upper face, and wherein the concentrator node is housed in a container attached to the lower face of the bogie frame; - the communication interface comprises a pair of directional Wi-Fi antennas reciprocally oriented in opposite directions along, or parallel to, a driving axis of the bogie.