“The transition from diesel to electric trains occurred over just a few weeks ... Apte understood that they had a unique opportunity to observe rapid changes to the environment.

For four weeks, they tracked the rapid improvements in air quality as old diesel locomotives were replaced by new electric trains. "A lot of these transitions happen pretty slowly. This one ...

and is responsible for the “gear change” sound of many electric trains. We’re particularly taken by the sound of some German and Austrian locomotives (made by our corporate overlords Siemens ...