Bus route Q1 is an excellent bus service that runs every 10 minutes from Central Station to the north and south quays on the banks of the Tyne. The route for this service Q1 is Central Station - Theatre Royal - Grey Street - Quayside (north bank) - Hillgate Quay - The Baltic - Gateshead College - Gateshead Interchange.
It's quite a steep walk between the city centre and the Quayside so on the way back up especially you may want to take one of the bright green Quaylink Shuttle buses. These are also useful if you want to go a bit further afield e.g. to the Baltic Gallery. There are two routes:
Service Q1 runs from Newcastle Central Station to Gateshead Interchange via Baltic and The Sage
Service Q2 runs from Haymarket Bus Station to Ouseburn (an up-and-coming arty area) via Newcastle’s East Quayside area
Buses run every 10 minutes during the day, every 20 minutes in the evening (until about midnoight).