How long will it take me to get from lama temple to Beijing west train station?

If by subway, take line 5 at Yonghegong Station, get off at Ciqikou Station. Then transfer to line 7 to West Railway Station. Generally speaking, the whole trip takes around half an hour. The ticket fare is CNY 5 per person.
In addition, you are advised to arrive at the train station 1 hour in advance. Thus you can start off at around 11:30 to 12:00 in the morning.