Re: Bring it on
A good proportion of the lines that carry the majority of freight containers can carry the W10 (Network Rail sizing) containers
Thus, many of the gauge issues have been resolved over the past 20years.
you might like to look into the 'standard containers'. There is a large number of 'standard sizes'
HS1 (Channel tunnel) link is built to UIC-C gauge. HS2 will be the same.
Oh, O.V. Bullied, CME of the Southern Railway experimented with two deck EMU's for services into Waterloo. They were not very popular and only 2 units were built.
Even the French can't get it right as the latest EMU's built for them couldn't be used because the stations on their proposed routes couldn't accommodate them.
Yes a good proportion of French, Belgian and Dutch commuter trains are duplex but not everywhere by any measure