"We have received intelligence inputs from Delhi. Some suspected terror groups in Mysore have threatened to carry out blasts on some trains. Our officers are on alert, especially in Mysore," DIG (Railways) B Srikantappa told reporters here.
Srikantappa said tracks are being inspected along with the Regional Security Commissioner.
"We have to be alert on the eve of August 15. As we will be busy with security that day, they (suspected terror groups) might exploit this opportunity," he said.
Srikantappa said extra police force was being sent to Mysore.
Round the clock vigil is on at railway stations across the state, especially Bangalore and Mysore. Passengers are being thoroughly checked as also their luggage, he said.