From
http://www.td.gov.hk/en/transport_in...017/index.html
"1. Additional Charge for Baggage:
In general, additional charge for baggage may be levied on:
> every piece of baggage that is carried inside the baggage compartment; or
> every piece of baggage with total dimensions (length + width + height) exceeding 140cm that is carried inside the passenger compartment."