On a very hot summer day, railroad tracks can buckle, causing train delays

and derailments. Select the best reason below for the buckling.

The metal rails undergo thermal expansion APEX Verified

The best reason for buckling of rail tracks on hot summer days is the thermal expansion or compressive forces acting on the rail tracks.

Explanation:

The rail tracks are composed of metals and they are rigidly connected with each other. If the materials used in construction of rail tracks are old, then there can be weakening of the track materials leading to decrease in their resistivity to thermal heat.

So this increase in temperature on hot days leads to compressive stress on the tracks which causes the tracks to expand and misaligned themselves.

Also the loosening of the ballast, ties and fasteners enhance the speed of buckling on hot summer days. Thus due to thermal expansion of the materials of the tracks, they buckle up as there is no space for desired expansion.