President Pranab Mukherjee on Thursday said that Indian Railways can truly be called the "unifiers of the nation"."It connects people across the length and breath of the country with a rail network of more than 66,000 km. The Railways continues to be the main source of connectivity for people as well as the movement of goods," Mukherjee said while addressing a group of probationers of different Railway Services, who had called on him at Rashtrapati Bhavan, according to an official release.The President said that the probationers should always remember that people have reposed tremendous trust in them and therefore, should carry out their responsibilities with dedication and ensure punctuality and safety of passengers.Noting that they would confront new problems as the world is changing fast, he told them to be able to meet those challenges with a "spirit of innovation, an open mind and willingness to learn". "The nation expects them to face the challenges with fortitude as they are the agents of change," the release quoted Mukherjee as saying.