Rahul took a local train towards Ghatkopar from Andheri station via Dadar to reach his second programme venue.
As per the original plans, he was scheduled to fly in a helicopter.
He travelled on the Virar-Dadar fast train in a second class compartment along with the general public, and got off 15 minutes later around 1:15 p.m. at Dadar.
Railway officials said they were not informed about it by his security personnel.
Earlier, several Shiv Sena members were arrested as Congress leader Rahul Gandhi arrived here after Sena threatened to show him black flag and disrupt his schedule.