This image was acquired from
wikimedia. It was marked as Public Domain or CC0 and is free to use. To verify, go to the source and check the information there.
Helsinki Metro signal Po .svg en Helsinki Metro primary signal showing the aspect Po fi Helsingin metron popastin nytt opastetta Po Selfmade in Inkscape Based on several source photos and raitio org htm Mysid Helsinki Metro Diagrams of railway signals in Finland
Page 2023 Free-images.com. All images are Public Domain