Gridinia Bay Junction is a massive junction in Gridinia Bay. Built with the theme of castles (honoring the founding Gridinia Castle), it serves as a junction for the Standard Gauge railways, the Crotoonian Hills Narrow Gauge Railway, and the bus services (both forms of transport having their own designated zones). Railways transfer passengers and goods among the four platforms (and a standard gauge marshaling yard), and bus services are taken care of in an arched shelter. It also serves as a terminus and headquarters for the Crotoonian Hills Narrow Gauge Railway, with a large railway shed and engine yard.
It appeared several times in the series so far; for example, Casey Jr delivered a parcel for the UK here in Casey Jr's Mail Run, and in Tillie's Tricky Travels, it is stated that Tillie has several friends here.
Piper works shunting duties here.