AviK: Belated answer to your comment about the driver (of the train, I assume) doing a melocho “doiraisa”. This is irrelevant as the drivers of those trains are overwhelmingly gentiles. As with a mill owned by a gentile,it would be Muttor.
As far as the story of the doctor and the rov, I am surprised at your assertion that it is preferable to call an ambulance rather than drive a car. Clearly, “bemokom pikuach nefesh” one does not wait and the doctor drove himself to save time.