This route has been proposed variously as either a tunnel or a bridge. A 2010 report by the Centre for Cross Border Studies estimated building a bridge between Galloway and Ulster would cost just under £20.5 billion. The proposal would see passengers board trains in Glasgow then cross on the bridge via Stranraer and alight in Belfast or Dublin. A longer bridge already exists between Shanghai and Ningbo in East China. Some political parties in Northern Ireland have included the bridge in their manifesto for some time. However, because of the Beaufort's Dyke sea trench which is approximately deep, this route would be deeper than the southern routes between Wales and Ireland. The sea trench was also used for dumping munitions after World War II, and so would require an expensive cleanup operation. Ronnie Hunter, former chairman of the Institute of Civil Engineers Scotland, suggested that the project was a "stretch but doable". He cited the lack of "soft rock, the chalk and sandstone" as a challenge compared to the construction of the Channel Tunnel. He also suggested that the change in rail gauge between Ireland and Great Britain might pose further concerns. Such a project was considered by railway engineer Luke Livingston Macassey in the 1890s as "a rail link using either a tunnel, a submerged "tubular bridge" or a solid causeway". The north channel crossing was the subject of a 2020 study by the United Kingdom government.