Subway

The Metro the subway is the railroad that there are most in the underground of the route for short.
The existing section can refer the tunnel section of the railroad and a station under the ground to a subway if I interpret it in a broad sense, but there is much it and points at the whole seen route in many cases in the area around the big city.
In addition, I become the subway if most run in the basement even if a part runs through ground and an elevated part.
The route via the basement is not suitable for a sightseeing use without there being scenery to run a basement, but service is possible at the place where service is difficult at the appointed hour at the appointed hour, and I compare the danger of the traffic accidents such as grade crossing accidents with a ground pike, and the centers of the big city where a city area crowds are originally low because there is not roads through the existence such as a railroad crossing or the traffic light mutual interference with the transportation system of others like a route to go along on a viaduct.
In addition, I am different from a route running on the ground, and I do not receive a strong wind or the influence by rain / snow / the fog either, and this point contributes to characteristics security at the appointed hour.
Because visibility at the time of the driving is bad, the security such as signals tends a safer thing to be adopted, and the danger of the collision is low.
However, when there is deficiency to drainage to run in the low place, I am in danger of the flood, and in late years a menace of the terrorism is recognized.
In addition, there are many insufficient old subways of the fire prevention equipment in Europe and America, and there is the place where there are a wooden vehicle and elevator.