I am looking to book my trip from Hong Kong to Guangzhou via train

Is that train considered a high speed train? If so, do they usually have an option for checked luggage? I am traveling one way to fly out of Guangzhou so will have a rather large (about 20kg) suitcase with me and want to make sure that it will be on the same train as me. Or will I have to arrange for it to be transported a different way? I plan on booking Business Class.