>>2052642Incredibly stupid idea. Imagine a fairly standard intercity train, such as a 12 car long German ICE 4. It's 346m long in this config, and carries about 830 passengers.
Let's be generous and say the train has an average occupancy of 70%. That's 581 people. Of those, let's say 1/3 would like to bring their car with them. But those that want to be with their cars are generally couples or families, so let's say each car on average has an occupancy of 3.0 people. That brings us to 65 cars needed on top of the 12 car 346m long train. Can you imagine how much time and additional infrastructure would be needed to fit those cars on a special traincar?
Forget about intermediate stops obviously, as it would take like 30 minutes at each stop.
There's a reason they've almost all dissapeared since highways. It's a logistical nightmare. Requires superlong platforms with special car ramps (meaning you end up having to stick stations in inconvenient industrial areas).
About the only use are routes where train transport is the only option, such as the train track only channel tunnel.
Even then, it's such a hassle I imagine many people prefer the ferry as it's cheaper and wayt easier to load you car unto.