Rail transport is often considered more sustainable than other transport modes, especially air transport. If one compares the operation consumption of trains and aircrafts only, this is inherently true. The present paper presents an unconventional methodology to assess the preferable solutions evaluating the embodied energy of the transport infrastructures, so as to calculate the Lifecycle Energy Requirement of air and rail transport services. The methodology is then applied to an imaginary transport service between two cities, and benchmarked against different transport supplies provided and various morphological condition of the territory affecting the complexity of the rail infrastructure