The tunnels are passages for trains under mountains, hills and rivers. The tunnels are dark but the trains are well lighted. Electric motors are often used, this avoids the smoke of steam engines which is very unpleasant in the tunnels.
The tunnels are passages for trains under mountains, hills and rivers. The tunnels are dark but the trains are well lighted. Electric motors are often used, this avoids the smoke of steam engines which is very unpleasant in the tunnels.