The incident is has taken place near the train cross road near the Kandy police.
The mother (36) had attempted to push her son before a moving train when two constables on duty nearby had intervened and saved the child.
Speaking to media, PC Sampath Mawekumbura has said that they had seen the woman beating and dragging the child to the crossroad. They had moved closer after this raised their suspicions.
At the time, the Kandy - Matale bound 7.15 am train was near the area, reports add.
Mistreated
Initial investigations have revealed that the child's father is mistreating both the mother and child. Desperate after being unable to look after the child, the mother had attempted to him, investigations further say.