Selecting a BLDC Motor for a 350kg Energy-Efficient Vehicle

Hello!
My name is Albin Johansson, and I am a student at Dalarna University in Sweden. I am part of a project called Eximus, to create an electricity-driven vehicle that is as energy-efficient as possible.
As a part of that project, we require an electric motor. Since the vehicle is supposed to be as efficient as possible, we'd like some information as to which motor would be best for our purpose.
The motor is required to be driven by a 6-48 V battery with a maximum current of 20 A, though a lower current would be preferred since the vehicle is supposed to use as little energy as possible.
The motor should be able to power a vehicle with a total weight of up to 350 kg, driving on train tracks.
Previous vehicles have managed to drive using power as low as 20 W, though we assume that the motor will need to be able to achieve a higher power than that.
Any advise is appreciated!

Hello!
My name is Albin Johansson, and I am a student at Dalarna University in Sweden. I am part of a project called Eximus, to create an electricity-driven vehicle that is as energy-efficient as possible.
As a part of that project, we require an electric motor. Since the vehicle is supposed to be as efficient as possible, we'd like some information as to which motor would be best for our purpose.
The motor is required to be driven by a 6-48 V battery with a maximum current of 20 A, though a lower current would be preferred since the vehicle is supposed to use as little energy as possible.
The motor should be able to power a vehicle with a total weight of up to 350 kg, driving on train tracks.
Previous vehicles have managed to drive using power as low as 20 W, though we assume that the motor will need to be able to achieve a higher power than that.
Any advise is appreciated!
We can provide a 24V or 48V brushless DC motor, but we need to know the required motor power capacity, speed, output torque, and other parameters so that we can recommend a suitable motor to you. See our BLDC motor's different models, and prices at: https://www.ato.com/high-torque-bldc-motors