On its north end, the base tunnel (BBT) has two entrances, which must go underground a few kilometres before the junction with the main tunnels, and will also be built as part of the BBT. One route leads from the main Innsbruck station under Bergisel and the other connects with the Innsbruck bypass. This route adds about more to the length of the tunnel than the Innsbruck station route; with it included, the BBT, at , would become the longest continuous railroad tunnel in the world. However, if the Axentunnel extension is added to the Gotthard Base Tunnel, its length would become , allowing it to reclaim the 'longest tunnel' title.