beijing-bound passengers from hong kong may order tickets from an online reservation system operated by the mtr corporation. the system is limited to the one-way, hong kong to beijing trips only. ordering of tickets requires extensive registration, including a credit card number, and tickets can only be delivered in the hong kong sar, which makes it impossible for most non-hk resident customers to order. travellers for beijing may purchase northbound tickets at a dedicated counter at hung hom station, whilst southbound tickets from beijing to hong kong can only be purchased in beijing or from travel agencies.