The Roar Of Underground Trains

The UBahn lines in Berlin cover the city connecting with Sbahn , buses and trams .My picture shows part of the U1.The eastern part of this  route is built above ground and is the oldest part of the UBahn network .After a while the BVG dug and maybe blasted tunnels.for later lines . UBahns are yellow and walking under these ancient lines ( ideal in the heat ) you hear and feel the roar of these yellow trains as they thunder overhead Almost like huge roaring dragons , or how I imagine they'd sound :
Thanks to laurie54 for hosting the challenge.