[alexander_busek]

The devil is in the details. If there are human passengers, there is the time taken to move up to 3,000 kilometers per second. While moving up to the cruising speed, G-forces will be experienced by all humans. Will they be able to walk around during this period? I think not. The same goes for the deceleration phase. I suspect, if someone does the math, the time for acceleration and deceleration will take up more than a few hours.

The real point is that, if you have to first accelerate to 3,000 km/s - i.e., if you are able to first accelerate to the cruising speed - you don't even need to "hook up" with the space train: Just continue cruising at 3,000 km/s in the frictionless vacuum of space.

Until shortly before you reach your destination, in which case you will have to deccelerate anyway.

Regards,

[TalonDJ]

“The real point is that, if you have to first accelerate to 3,000 km/s - i.e., if you are able to first accelerate to the cruising speed”

Exactly!
If you can already get ‘cars’ up to that speed and decelerate them... why link them to a train ever? Just fly around in the cars and call it a day.