A safety device for monitoring a crossing point of a railway network and comprising: - One, preferably a plurality of sentinel apparatus, which is installed along the route made by the train in correspondence of the crossing points, each sentinel apparatus comprising an image acquisition device and transmission means for transmitting the images acquired; - A receiving device, which is installed on the train, and configured so as to acquire the images sent by the transmission means and display them on a screen; - Activation means (11, 12, 13, 14) configured for enabling the receiving device to receive the images only sent by only one sentinel apparatus in correspondence of the approaching of the train, along the motion direction, of a pre-established activation distance from the said sentinel apparatus, so that, once the said activation distance has been reached, the screen displays the images acquired from said image acquisition device and relative to the said crossing point, and; - De-activation means (11, 12, 13, 14) configured to de-activate the reception of the said images in correspondence of the overcoming of the said sentinel apparatus of a pre-established minimum de-activation distance; - wherin the receiving device comprises: - A monitor provided with a screen for seeing the images; - A receiving channel for receiving the images sent by a sentinel apparatus; - A GPS receiver for receiving a current position signal from a satellite; - characterized in that the receiving device further comprises: - A memory containing the placement coordinates of the said sentinel apparatus; - And wherein a processor is further provided, configured to compare the coordinates received from the satellite with the ones contained in the memory so as to configure the monitor to the reception of the images of a specific sentinel apparatus in correspondence of the reaching of the train of the activation distance from the said sentinel apparatus and de-activating the monitor once the train has reached the de-activation point and the processor has recognized such a condition. - One, preferably a plurality of sentinel apparatus, which is installed along the route made by the train in correspondence of the crossing points, each sentinel apparatus comprising an image acquisition device and transmission means for transmitting the images acquired; - A receiving device, which is installed on the train, and configured so as to acquire the images sent by the transmission means and display them on a screen; - Activation means (11, 12, 13, 14) configured for enabling the receiving device to receive the images only sent by only one sentinel apparatus in correspondence of the approaching of the train, along the motion direction, of a pre-established activation distance from the said sentinel apparatus, so that, once the said activation distance has been reached, the screen displays the images acquired from said image acquisition device and relative to the said crossing point, and; - De-activation means (11, 12, 13, 14) configured to de-activate the reception of the said images in correspondence of the overcoming of the said sentinel apparatus of a pre-established minimum de-activation distance; - wherin the receiving device comprises: - A monitor provided with a screen for seeing the images; - A receiving channel for receiving the images sent by a sentinel apparatus; - A GPS receiver for receiving a current position signal from a satellite; - A monitor provided with a screen for seeing the images; - A receiving channel for receiving the images sent by a sentinel apparatus; - A GPS receiver for receiving a current position signal from a satellite; - characterized in that the receiving device further comprises: - A memory containing the placement coordinates of the said sentinel apparatus; - And wherein a processor is further provided, configured to compare the coordinates received from the satellite with the ones contained in the memory so as to configure the monitor to the reception of the images of a specific sentinel apparatus in correspondence of the reaching of the train of the activation distance from the said sentinel apparatus and de-activating the monitor once the train has reached the de-activation point and the processor has recognized such a condition. - A memory containing the placement coordinates of the said sentinel apparatus; - And wherein a processor is further provided, configured to compare the coordinates received from the satellite with the ones contained in the memory so as to configure the monitor to the reception of the images of a specific sentinel apparatus in correspondence of the reaching of the train of the activation distance from the said sentinel apparatus and de-activating the monitor once the train has reached the de-activation point and the processor has recognized such a condition.