Madrid Metro has approved a pilot scheme to install in-tunnel advertising between two stations on  its underground rail network.
An LED advertising system will be installed between the stations Nuevos Ministerios and Colombia on Line 8, allowing video advertisements to be beamed to passengers onboard trains passing through the tunnels.
The two-year trial is expected to generate around €400,000 in additional income for Madrid Metro.
It is the first time in-tunnel advertising technology has been tested in Spain.
Digital Underground Media will fit the new system. The advert is activated as a train passes through sensors in the tunnel. The sensors tell the LED pillars how fast the train is going so the system can sequence the images in sync with the passengers on board.
