what route to be taken to reach tangshan from beijing airport thru railway?

Well, do you refer to Nanyuan Airport? If so, you can take a taxi to BJ Station first, and it takes about 20 minute, CNY40-50. Then you can take a bullet train to Tangshan, which takes about 1h 10 minutes- 1h 40 minutes and costs CNY52.5 /62 for a first class seat, CNY44.5/52 for a second one.