Can somebody please tell me where will CBP check me and how?
Directly at the train station before you're allowed to board, similar to how it works in Canadian airports for flights to the US.
Is the CBP check before boarding the train, or on the train or do I have to step off the train at the border?
You don't have to step off the train at the border, however the train will make a stop at Blaine/Peace Arch in order for customs to collect your declaration and inspect your luggage if necessary. There are no other stops between Vancouver and the border, although the train does make a few stops within the US.
Will I have fill out an I-94W and biometrics (I do that at the Canadian airport, so would I have to do it again)?
- If you have a valid I-94 from your previous trip, you don't have to fill out anything
- If you have no valid I-94 and no ESTA, you'll need to fill out form I-94W and submit your biometrics
- If you have no I-94 but do have an ESTA, you'll receive a fresh I-94 after answering some questions about your trip and submitting your biometrics
Does having an ESTA help me with anything to expedite passing?
It will make crossing the virtual border slightly faster, but the train leaves on a fixed schedule so whether or not you'll spend an extra five minutes on your feet probably wouldn't make a difference in the end. You can also save a bit of time by applying for an electronic I-94 in advance.