Yes, exactly. And once it's in compression even at higher temperatures it will often be fine if left alone. This is why railway companies impose speed restric

Yes, exactly. And once it's in compression even at higher temperatures it will often be fine if left alone. This is why railway companies impose speed restrictions when it gets hot - they don't want the dynamic load of a passing train to exceed the ability of the track bed to resist buckling. Running at low speeds helps in this respect.