Linha do Norte

Santa Apolónia railway station, Lisbon, Linha do Norte starting point.
Line length	336,079 km (208,830 mi)
Track gauge	1,668 mm (5 ft 5 21⁄32 in)

Linha do Norte is the Portuguese main railway track that connects the two main Portuguese cities, Lisbon and Porto. Its length is 336.079 km. It goes through some other important cities like Vila Franca de Xira, Santarém, Entroncamento, Pombal, Coimbra, Aveiro, Espinho e Vila Nova de Gaia, among others. It constitutes the backbone of the Portuguese railway system of freights and passengers, running daily hundreds of wagons of both types.

As part of the plans for a high-speed rail network, there will be a parallel high-speed line (up to 300 km/h) to relieve this main line, since it has reached a saturation threshold where it's impossible to add new freight wagons without jamming the fast passenger services (InterCidades and Alfa Pendular).