[Pet_Ant]

What about if they added “wings” to trains? That could generate some lift reducing the effective weight is my shower thought.

No idea how much the wings would add versus the lift help.

[NuclearPM]

The friction is almost entirely from drag/air resistance, not from the resistance of the rails.

[bluGill]

the losses from weight are linear with speed - at high speed completely dwarfed by losses from pushing air out of the way which is quadradic with speed.

the wings on race cars are poited down - they increase weight to keep the car on the ground at the expense of more drag, which they overcome with a bigger engine (and more fuel use)