【明報專訊】FOUR days after the Hong Kong section of the Express Rail Link (XRL) came into service, there are still a lot of practicalities that have to be resolved. Some passengers are still unable to carry their oversized luggage onto the train. Passengers who booked via the official website on the mainland still have to line up in long queues at West Kowloon Station to collect their tickets. It takes time for the ridership of the Hong Kong section of the XRL to go up. It is unrealistic to expect the number of passengers to increase substantially in a year or so. However, if the experience of the passengers is too bad and the XRL gets negative reviews because of passengers' poor impressions, it will put people off. The MTR should negotiate with China Railway about how to tackle the problem as soon as possible. The opening of the XRL marked the integration of Hong Kong and mainland China. On the face of it, issues of tickets and luggage rules are technical problems. Yet they involve the deeper differences between Hong Kong and the mainland. The experience of streamlining the operation of the Hong Kong section of the XRL can serve as a lesson for the future integration of the Greater Bay Area.