CCTV footage of frantic rescue attempt by off duty policeman and fellow commuters emerges after woman faints and falls onto a train line.

Spanish police have released a clip of the officer leaping onto the rails and rushing to the stricken woman's aid despite a train being due to arrive just seconds after her fall.

The unnamed 52-year-old woman fell head first onto the tracks after collapsing while waiting for a Madrid Metro train at the city's Marques de Vadilla station on Monday afternoon.

Some commuters rush to the platform edge desperate to help the woman who is seen lying prone on the rails, while others run off to find help.

But, without a seconds thought for his own safety, the unnamed 39-year-old policeman, who was stood at the other end of the platform, sprang into action.

He is seen leaping down onto the tracks close to the entrance of the metro tunnel and sprinting along the rails.

Just as he reaches the woman the lights of an approaching train begin to emerge from the tunnel.

But fortunately for both the policeman and the woman he is trying to rescue, other commuters managed to get the train driver's attention by waving frantically and he is able to bring the train to a halt in time.

The policeman manages to drag the woman, who is unconscious and a dead weight, across the tracks and is helped by other rail passengers as he manages to lift her to the safety of the opposite platform from where she fell.

Fortunately a doctor was on hand at the station to treat the injured woman before paramedics could come to her aid.

The Metro de Madrid is the sixth longest underground rail network in the world and serves almost 650 million passengers each year.