HONG KONG AIRPORT TO SHENZHEN NORTH RAILWAY STATION

I believe there is a high speed bullet train in operation from Hong Kong airport to Shenzhen North Railway Station. Is this correct? Also how long does this take and what is the cost? There is no clear information online and its thus confusing reading from the above threads. Also kindly advice if there is a coach/bus from Hong Kong Airport to Shenzhen North Station and again the cost and length of time it will take since i arrive into Hong Kong Sunday 12th October at 4.30pm.