What are scientific reasons that railroad tracks can buckle on very hot summer days and then cause train delays and derailments?

Answer 1

Buckling was caused by the expansion of the rail due to being heated by the sun. The metal rails undergo thermal expansion. This can cause rails to also pull against the metal pins holding the rail in place and shift the rails away from the (timber) railroad ties. The ties and rails define the train's pathway, and the rails, without expansion, keep the train's "wheels" in contact with the rails; with expansion, this direct contact cannot be maintained. Add in speed and heat from friction, expanding rails can derail a train faster than an Engineer can blow the emergency whistle or faster than he can apply the brakes.

Answer 2

Railroad tracks can buckle on hot days because the metal expands in the heat, causing it to lengthen and push against the surrounding tracks and structures. This can result in the tracks bending or buckling. If not addressed promptly, these buckled tracks can lead to train delays and even derailments due to safety concerns and potential damage to the train cars.