A method of transmitting a trigger message in a network of operatively interconnected node devices arranged along at least one elongated geographic track, wherein said node devices are divided into a plurality of groups, wherein each group comprises a first edge node device and a second edge node device corresponding respectively to the first node device and the last node device, seen in the moving direction of said object, wherein said each group comprises other node devices, wherein each of said first edge node device and said second edge node device comprises a sensor for detecting said object; wherein said trigger message is configured for, when received by said node devices, triggering a service provided by said node devices to an object moving along said geographic track, the method comprising the step of: - upon detecting said object by a sensor of a first edge node device in an immediate preceding group, transmitting, by said first edge node device in said immediate preceding group, an object-detected trigger message, wherein said object-detected trigger message is a broadcast message; - in response to receiving said object-detected trigger message at least from said first edge node device in said immediate preceding group, transmitting, by a second edge node device in said immediate preceding group, a first object-approaching trigger message, wherein said first object-approaching trigger message is a unicast message destined to a first edge node device in a group; - receiving, by said first edge node device in said group, said first object-approaching trigger message; and - transmitting, by said first edge node device in said group, a second object-approaching trigger message to said other node devices in said group, wherein said second object-approaching trigger message is a broadcast message; wherein said first object-approaching trigger message and said second object-approaching trigger message are configured to trigger said service for a determined period of time, a period of time of said service triggered by said first and second object-approaching trigger messages (16, 17, 18) is longer than a period of time of said service triggered by said object-detected trigger message. wherein said node devices are divided into a plurality of groups, wherein each group comprises a first edge node device and a second edge node device corresponding respectively to the first node device and the last node device, seen in the moving direction of said object, wherein said each group comprises other node devices, wherein each of said first edge node device and said second edge node device comprises a sensor for detecting said object; wherein said trigger message is configured for, when received by said node devices, triggering a service provided by said node devices to an object moving along said geographic track, the method comprising the step of: - upon detecting said object by a sensor of a first edge node device in an immediate preceding group, transmitting, by said first edge node device in said immediate preceding group, an object-detected trigger message, wherein said object-detected trigger message is a broadcast message; - in response to receiving said object-detected trigger message at least from said first edge node device in said immediate preceding group, transmitting, by a second edge node device in said immediate preceding group, a first object-approaching trigger message, wherein said first object-approaching trigger message is a unicast message destined to a first edge node device in a group; - receiving, by said first edge node device in said group, said first object-approaching trigger message; and - transmitting, by said first edge node device in said group, a second object-approaching trigger message to said other node devices in said group, wherein said second object-approaching trigger message is a broadcast message; - upon detecting said object by a sensor of a first edge node device in an immediate preceding group, transmitting, by said first edge node device in said immediate preceding group, an object-detected trigger message, wherein said object-detected trigger message is a broadcast message; - in response to receiving said object-detected trigger message at least from said first edge node device in said immediate preceding group, transmitting, by a second edge node device in said immediate preceding group, a first object-approaching trigger message, wherein said first object-approaching trigger message is a unicast message destined to a first edge node device in a group; - receiving, by said first edge node device in said group, said first object-approaching trigger message; - transmitting, by said first edge node device in said group, a second object-approaching trigger message to said other node devices in said group, wherein said second object-approaching trigger message is a broadcast message; wherein said first object-approaching trigger message and said second object-approaching trigger message are configured to trigger said service for a determined period of time, a period of time of said service triggered by said first and second object-approaching trigger messages (16, 17, 18) is longer than a period of time of said service triggered by said object-detected trigger message.