The constable, Rajeshwari Sarode, fell victim to this malicious practice on Friday. But Venmurugan Ajum (20), who hurled the stone at her, didn't know what hit him when the infuriated constable returned to the spot and flung him in the slammer.

Sarode boarded the train at around 11.50 at Mumbai Central en route to Churchgate where she was posted for duty. As is the convention, she stood on the footboard, scouring the tracks for sadistic miscreants armed with stones. When the train pulled in at Charni Road, Sarode spied Ajum standing along the tracks just beneath her. As the train pulled out, he aimed a stone at Sarode, hitting her just below her right eye. Recovering her composure, she spun around and identified the man as a contract worker with the railway.

``He was a dark man, dressed in green shorts and banyan,''Sarode told The Indian Express. Intent on reporting to work on time, Sarode rode to Churchgate, logged her arrival and then set off for Charni Road with a colleague, Naina Patel.

``He had some gall to stone a constable... ``He probably thought he could get away with it because I am a woman. Therefore, I was determined to catch him myself,'' says Sarode, whose sensibilities are more grievously injured than her cheek. That, she adds, explains why she did not ask her male colleagues for help.

At Charni Road station, Sarode found Ajum repairing a fence, and hauled him to the RPF booth on the platform. ``Though he was a little defiant at first, he finally admitted to throwing the stone,'' she says. However, despite Ajum's confession to Sarode, he refused to make a confession before the officer recording his statement.

Sarode says Ajum told her he had thrown the stone in jest `to pass time'. ``But'', she points out, ``that's not what it looked like when he aimed at me.'' When Ajum realised the gravityof the situation, he tried to shake himself free but Sarode and Patel held on. Then, tying his hands, they took him to the RPF's Grant Road office under whose jurisdiction Charni Road station falls. Ajum's statement was recorded there.

Ajum has been arrested under Section 152 of the Indian Railways Act which prohibits throwing missiles at commuters on trains.

He has been placed in judicial custody at the Arthur Road prison. He will be produced before a magistrate's court in Mumbai Central on Monday. The offence carries a maximum punishment of 10 years imprisonment.

Friday's incident follows four previous ones on the Western Railway between Bandra and Dahisar during the last two months. According to a survey done by the Government Railway Police, about 150 incidents have been reported in five years but only 10 arrests have been made. These cases have resulted in conviction.