Try to take some pictures - the railway station, railway bridge together with the tracks with my 100-300mm lens from a long distance, but this photo turn out more interesting (two photographers shooting each other with their camera).
This was used to be the old KTM railway running next to the Ghim Moh HDB estate. Using CPL filter hope to bring up the contrast from the ground, which CPL filter do fine to darken the color of the grass, but fail to darken the blue sky.
Same location and same direction but GND filter added, from the photo it help to further darken the sky and it did balance the brightness between and the ground.