From the Introduction: Although the surrounding lands sure are quite dry and arid a small river has dug has dug a small canyon into the landscape here. To allow trains to cross it enterprising engineers built a wooden bridge across the gorge. Only a layer of thin boards hides the fact that the bridge is nothing but a framework of wooden beams, moving and squeaking whenever it has to bear a heavy load. Still, the construction is sturdy enough and has stood for quite a few years and it will probably last for at least a few decades more.