If left without gaps, the expansion would either lead to derailment or wear and tear of the tracks.
In modern tracks there aren't any gaps. Installing certain low thermal expansion metals or alloys as the materials of the tracks, we can avert the situations. In continuous welded rails, the tracks are stretched to sides before summer begins.
The stronger a light shines the darker are the shadows around it.
A blunt knife or rusted knife can't be useful for anything just for the sake we call it as the knife similar to PayTM series or Sachin or Virat records.
'Idhuvum Kadandhu Pogum "
Even this challenging situation would ease
Caution: Explosive. Handle with care.