Although taking the same basic idea from Snakes on a Plane (lots of deadly snakes loose on a claustrophobic, high speed means of transport), the background story of how the snakes end up on the train is completely different.
The sequel to The Snake King's Child, after Vaha and Soriya married, they gave birth to a boy and named him, Mek. However, Vaha, then, married another woman and gave birth to another boy named Sok but the new wife got jealous to Soriya and stole her ring. Suddenly Soriya turned to the snake and Vaha dropped dead by a heart attack. The new wife took everything and blamed Mek as the servant.