Palakkad, Nov 2 (IANS): In a tragic accident, four contract cleaning workers who were engaged in cleaning the railway track were trapped on a railway bridge and run over by the speeding Kerala Express at Shoranur in Kerala's Palakkad on Saturday evening, officials said.

The dead include two men and two women, all of them hail from Salem in Tamil Nadu.

Both the male cleaning workers were named Lekshman, while the women were identified as Valli and Rani.

According to the police, these casual cleaning staff were picking up the litter on the railway track on the Kochi bridge above the Bharatapuzha river when the accident occurred.

Seeing the fast-approaching Kerala Express train coming from Delhi and bound for Thiruvananthapuram, these hapless workers were unable to take cover and all four were killed instantly.

While three bodies have been recovered, the search for the fourth body, which had fallen into the river, is currently going on.

These casual workers are attached to a railway contractor who had taken the cleaning job on either side of the railway track in the area.

As per reports, these workers did not realize that the Kerala Express was all set to pass over the bridge when they were walking on it.

The local police and the Railway Protection Force have begun a probe into the gruesome accident.

The accident came days after four passengers were injured after an explosion occurred inside a Rohtak-Delhi passenger train.

An official said that the explosion took place near the Sampla station soon after the train departed from Rohtak station.

Eyewitnesses added that the sudden explosion led to a chaotic scene while the train was immediately halted. Reports suggested that the blast may have resulted from a large quantity of chemicals that a passenger was carrying which had accidentally ignited and caused the explosion.