The idea of a lifting body design is to shape a vehicle's body in such a way as to produce lift without wings. Research has shown that this can be an efficient method of reducing drag while still providing lift.
This has typically done for aircraft or spacecraft:
Could a similar approach help to make trains more efficient?
Passenger trains already look streamlined and aerodynamic:
Freight trains do not:
Air resistance is not the only form of resistance that trains must overcome. They must also overcome the resistance of their wheels on the track. This is where I would think that the energy savings from a lifting body design would come from. Any additional lift created by the lifting body design would reduce the friction between the wheels and rail, thus saving energy.
Train wheels have flanges on them, so they don't need traction to steer. The cars also don't need traction on the rails since the driving wheels are only on the engines.
Could a lifting body create enough lift at typical train speeds to make a noticeable difference?