Why trains are more expensive to use than airplanes or buses?

The true and crude answer to this question is politics. It's far from being technical. Airplanes and buses emit a lot of CO2 and pollutants through the burning of fossil fuel and these externalities are not totally paid by the passengers. Trains are by default electric, which in cases like Europe, that electricity may come from wind power or hydro energy sources. Furthermore in airplanes there's a lot of competition, the business is very active and the non-profitable routes are by default not made or shutdown. Of course, the means through which the vehicle travels in the airplane industry, in this case the "free air", also allow higher flexibility for changing routes and lowering costs. In trains nonetheless, the state imposes routes to small cities and places that provide huge deficits to the company, according to what the state considers the public interest. The means through which the train travels are either not free, and normally these rails are owned by a single company which may almost impose its prices. Regulators also oblige trains to have a lot of staff, which in many cases is superfluous due to technology, even the machinist is redundant nowadays, like it is clear in many new train systems. A third of the train ticket might just go to pay high salaries for the train staff, even if many collaborators are not that specialised, like by merely selling or checking tickets. We talk now and then about self-driving cars, when such technology would be technically much easier to operate in trains, due to the moving restriction imposed by the rails.

In a short, the socialist way of looking into the transportation sector made trains less competitive with the airplane and with the automobile, which is a technical paradox, considering the huge costs of operating an airline and the enormous costs of the road network and infrastructures. Though in the airlines industry the market is very active, companies come and go, competition is ferocious, which forces prices to go down, without losing on safety. Indeed travelling on the high competitive private airlines is safer per passenger-distance than travelling on the highly subsidised public trains. In Europe that is clear, as the big train companies are almost all public and the airplane companies are almost all private. Furthermore the car driver is far away from paying the true externalities of automobile usage. Contrary to what drivers often say, cars are highly subsidised with public funds for roads and highways, very expensive viaducts, tunnels, semaphorisation, police road patrols or paramedics, not excluding the high economic costs car users don't pay with the huge car fatalities on roads. And that economic distortion provokes a low cost for car usage which also contributes to the high price of trains, since trains also compete with cars. And if car usage were more expensive, train usage would be more intensive and the train price per passenger-distance would be lower. Trains also allow higher comfort as compared to airplanes since there's no need to check-in or go through security control and normally train station are in the city center, not in the suburbs.

Again the answer to the question is politics. Further, trains have a "politico-economical defect" as, contrary to cars or airplanes, the majority doesn't run on petrol. By being independent from fossil fuels and being extremely efficient on energy consumption per passenger-distance, the train system provoked a setback to the economic paradigm based on consumption, mainly fossil fuels. Trains may be thirty times more efficient than cars, when energy is compared per passenger-distance and for standard vehicle occupancy, the energy in trains being normally electricity, which means trains are also much less pollutant. Thus, a true environmentalist doesn't promote electric cars, promotes electric trains, as trains consume much less energy per passenger-distance. And if trains are not flexible for small routes, like cars are, they are very efficient for passenger transportation between cities, now more than ever, as cities become more compact, dense and with more population. I.e., trains make economic sense between urban areas with high density of population, and cities in the last centuries demonstrated a tendency to become more compact. Trains also occupy much less space for transporting people, as compared with cars or buses, theoretically lowering costs, since land is an expensive asset in urban areas. So why are trains so much expensive, when compared for example with buses or airplanes? As stated, whilst buses and airplanes companies are mainly private without impositions from the state to operate on routes which have financial deficit, trains are obliged to do so. Trains normally run without concurrency and thus the companies may apply any tariff. The staff in many cases has benefits comparable to public servants, which means there's less labour flexibility as compared with the other private sector transport companies. And buses run also on highly subsidised motor-ways, since bus users are also far way from paying the true costs of road construction and usage.

In a short whilst the technical grounds tell us trains should be much cheaper, politics made trains unreasonably expensive. By the promotion of fossil fuels and an economic paradigm based on consumerism as the key factor for economic growth, highly inefficient means of transport such as the automobile had to be promoted, and efficient means of transport such as the bicycle for urban transport or the train for inter-city transport had to be demoted or even socially ostracised. The ideological approach made by the states was the most efficient one, since sophistic and pseudo-humanitarian argumentations would be highly valuable by the public opinion, forcing then train companies, normally public owned or with a high amount of regulations and impositions by the state, to have a low margin for profit. Yield management for instance is a common practise in all airliners, but not in all train companies. The states, mainly in the western world, also made huge and enormous public investments on roadways, practically neglecting investment on new railway. By being extremely safe, efficient and environmentally friendly, the train is undoubtedly the transport of the future. Let the politicians provide the train the same economic means and economic players we see operating in the bus or airline companies, and the prices will go down sharply and quality of the service will rise up. If we force a system for the railway more based on political, romantic or ideological approaches, and not based on technical and pragmatical points of view, we'll always have a decaying means of transport, even if the technical evidences per se tell us that train is one of the best, when analysing energy efficiency, safety, confort and emissions, system of passenger transportation.