score:12
As per this discussion:
I called the customs and border folks at the airport to see if they could give me a number for the train station. He said the train station doesn't have a number, and all the same people from the airport work there.
So if you call preclearance at the YVR airport at (604) 278-7422 then you will talk to the staff who will meet you at the train station. This makes sense, there are only two trains a day, it's pointless to maintain an entire CBP office at the station.
Upvote:4
Your best bet is probably https://www.cbp.gov/contact:
If you are unable to find the information you need [on cbp.gov], the CBP INFO Center is open Monday-Friday between 9 a.m. and 4 p.m. Eastern time. You can ask your question via email or by calling 1-877-CBP-5511 (877-227-5511). If you are outside the U.S. you must call 202-325-8000. (Telecommunications device for the hearing impaired: 1-800-877-8339 or https://www.federalip.us/)
Even if your question is specific to preclearance in the train station, the central help line should be able to find someone who knows the answer.