Calcutta, March 27 :     Railway Protection Force personnel fired ten rounds in the air to disperse an angry mob at Ballygunge railway station tonight after train services were disrupted for more than six hours in the Sealdah south section. Though no one was hurt in the firing, several persons were injured in the brickbatting. Sources said commuters turned violent after the authorities failed to inform over the public address system when services would resumed following an electrical fault on the overhead line between Park Circus and Bondel Gate railway crossing at 5.20 pm. The mob, which ransacked the station, also set on fire an electrical storeroom and some vends on the platform. Efforts to set on fire a stranded local train failed. Five fire engines were rushed to the spot to douse the flames. Normal services were resumed at about 11.30 pm.