Same one they have used all along! Think of it this way. You are trying to plow the big drift at Windy Point...starting, hitting it hard, stopping, and backing up. The Rotary whistle is the one that runs the show. It is obvious which whistle you hear when it is blown. Then the other engines follow suit. When they are moving along and need more speed or throttle you hear 2 whistles. Earl and John Bush can address that better than I. I would suspect it is the original whistle, but not sure. Again others more into that sort of thing can verify.
Greg
PS. My dad would call that a peanut whistle. But yes similar to something from the UK