There were several reasons that bridges and tunnels were important to railroads. The main reason was that without them, trains would not have been able to travel through mountains.
Railroads are unable to move up or down steep slopes. Bridges and tunnels permit them to avoid taking the long way around mountains or up and down the sides of valleys, which is what they would have to do otherwise to keep the tracks to a gentle slope only.
Due to the weights of the vehicles and the low coefficient of friction between a smooth steel rail and wheel, railroads are limited in the sharpness of curves they can follow and the amount of grade, or slope, they can climb.
Both bridges and tunnels are man-made to provide a way to get to a point that would otherwise be difficult or impossible to get to.
yes
Bridges and tunnels help carry transport, goods and people. This also shortens the amount of time to travel from a place to another. They also both have different types of bridges and tunnels e.g. bridges- suspension bridge, cable-stayed bridge, beam bridge, rope bridge, swing bridge, arch bridge e.t.c. tunnels- road tunnels, high tunnels, wind tunnels, network tunnels e.t.c. Every time you want to cross a bridge or tunnel you have to pay a toll to get through.
Mostly by bridges but there are some tunnels as well.
brooklyn
Aarya kota
The ones digging tunnels.
Franz-Georg Grenz has written: 'Infrastrukturinvestitionen und Umwelt' -- subject(s): Bridges, Cost effectiveness, Environmental aspects of Bridges, Environmental aspects of Tunnels, Tunnels
Get used to using tunnels.
plan bridges, tunnels, and dams
so they can start it from underground