Definition
A railroad tunnel is like a secret passage for trains 🚂, a covered pathway bored through a mountain or under a city. It's a shortcut that allows trains to travel through obstacles rather than going around them. Think of it as a bridge, but underground! Tunnels protect trains from weather and falling debris. They also reduce the steepness of railway lines. It's a pretty important piece of infrastructure, especially in areas with rough terrain. Without tunnels, many train routes would be impossible to build.