The cost of travel
Traveling by train requires a similar amount of energy per distance as that required of a bicycle, per person. The typical measure of transport efficiency is energy per unit distance; per passenger. This is usually expressed as Mega Joules per passenger kilometre (MJ/passenger-km). As a very rough guide walking might take around 0.78 MJ/passenger-km. Cycling slowly, at around 16 km/h, say, would require 0.11 MJ/passenger-km – let’s assume the determined commuter will be demanding double that. Working to those assumptions; locomotion by train, in fact for freight as well as for people, has remarkably high efficiency. The average train might require somewhere below 0.6 MJ/passenger-km, and newer trains are quite exceptionally efficient: When full, the trains in Basel require 0.085 MJ/passenger-km. The East Japanese Railway manages 0.35.
Simply for a little perspective the average car might demand two or three MJ/passenger-km; passenger aircraft around 1.4 MJ/passenger-km. No satisfaction can be taken, however, from the lower values of any of the modes of transport mentioned here because, whether fossil fuel or largely non-nuclear derived electricity, the source of energy is just as harmful for each… except arguably the humble bicycle, of course. Just to mention in passing, as if you couldn’t guess yourself, helicopters are among the least efficient.