Mumbai, Oct 26: The application of emergency brake derailed the engine of the Goa-Mumbai Duronto Express here on Thursday afternoon, disrupting the Konkan Railway network for nearly four hours, an official said. The engine driver was shown an emergency flag by maintenance workers after a rod got stuck on the railway tracks where some repair and painting works were underway, near Sawantwadi in Sindhudurg district, around 500 kms from here, said a KR spokesperson. "Accordingly, the driver applied the emergency brakes to stop the train and the engine got derailed. All other coaches were safe and there are no casualties," the spokesperson added. Work to put the engine back on the tracks and repair the railway track was taken up on a war-footing and completed within four hours, allowing normal operations to resume by 7 p.m. At least five long-distance trains, mostly serving the Goa-Mumbai sector were delayed by two to six hours in both directions.