Comment by nehalem501

Night trains won’t be high-speed TGV services, they will use the regular main lines. Track maintenance needs much less energy than building brand new lines. And yes, the carbon emissions per passenger are higher for high-speed trains compared to the regular ones, mostly because of their construction. Of course all of this works when the electricity produced by renewables or nuclear. If these trains are powered by electricity produced from coal, their carbon emissions are equivalent to using diesel trains.