Belle - I rode on Canada's VIA Rail Canadian train across Canada several years ago. I spent a lot of time in the domes during the day and at night. The domes were lighted at night by lights along the floor. This allowed passenger to see where they were stepping without blocking the outside view by reflected overhead light.
This means that lighting the domes from the floor area at night would be correct at least for the Canadian. I would suspect that the CZ domes had the same floor lighting scheme for the same reason. People viewing the train from the outside as it passes would see unlighted domes. The lower level of the dome car would have regular overhead lights.
NH Joe
