The law on the construction and financing of the four-metre corridor on the Gotthard axis comes into force on 1 June 2014. It reinforces the transfer of goods traffic through the Alps from road to rail - the objective of the NRLA. To allow semi-trailers measuring four metres in height and 2.6 metres in breadth to travel by rail between Basel and Chiasso/Luino, the tunnels need to be expanded, but numerous approach routes, bridges and platform roofs also have to be adapted to the necessary structure gauge.
« As shown in 1.1.2, semi-trailers with a corner height of 4.00 m will be used increasingly in unaccompanied combined transport because they offer clear logistical and economic advantages for shipping agents and haulage operators. »Federal Council dispatch, p. 3,844, 22.05.2013