how did people at station discriminate with dr.ambedkar?

Dr Bhimrao Ambedkar, one of the great leaders of India, shares his first experience of caste-based discrimination, which took place in 1901 when he was just nine years old. He had gone with his brothers and cousins to meet his father in Koregaon which is now in Maharashtra. They were well-dressed children. From their dress or talk no one could make out that they were children of the untouchables. 

Initially the stationmaster was quite sure they were Brahmin children and was extremely touchedBut on knowing thay they were Mahars the station master was stunned. His face underwent a sudden change. He was overpowered by a strange feeling of repulsion. There were many bullock-carts plying for hire. But among the cart men, not one of them was prepared to suffer being polluted and to demean himself carrying passengers of the untouchable classes.