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If it codes as travel and you have the Venture X then you could try the purchase eraser.
I don’t use that because there are many better ways to redeem points, but it might be an option for trains if you really want that.
Also, beware that a rail pass is not always the best option (even if it ends up cheaper).
I travel a lot within Europe and depending on where you are going train is not always the most convenient.
I like the flexibility of choosing the best mode (train, bus, plane, boat) based on the circumstances.