@WDP 20065 - Yes trekking and boarding of trains is banned. But we were fortunate that no one stopped us at Kulem station while we were starting the trek. Also bathing is not allowed at dudhsagar. RPF personnels and life guards are present there who stop everyone from going near the falls. If you want to take a bath at falls, you should go to the base of the falls through jeeps that start from Kulem Station. This means that you will not get an opportunity to trek along railway ghats. But just 500-600 m before dudhsagar falls (going from Kulem towards dudhsagar) there is a small waterfall just near the tracks where you can easily take bath and enjoy. We did the same.