sentences:  As their locomotives will no longer have to scale the gradients as they climb to 1,100 metres at the start of the current Gotthard Tunnel, freight trains will be able to grow to up to 750 metres in length depending on their load.The tunnel interior is also high enough to accommodate the four-metre-high trailers of articulated lorries, travelling straight through the Alps by train in 35 to 40 minutes.SBB is currently creating a four-metre corridor on the approximately 270-kilometre-long Gotthard line between Basel and the Italian border on behalf of the Swiss government, to be completed by 2020.