Vibration damage is wear, not a loss
Cracking in plaster or stucco attributed to years of passing freight is gradual deterioration, and every policy excludes it. There is no claim for it and there never was. It is a maintenance matter and, if the cause is genuinely identifiable, a question for the railroad rather than an insurer.
A derailment is a sudden event and a third-party claim
Damage from an actual incident is quite different: your policy responds to the damage and the responsible party can be pursued. Those are the claims where having your own cover matters most, because your insurer repairs now and recovers later rather than waiting on a liability determination.
Proximity can affect appetite and price
Some carriers rate or restrict properties very close to industrial rail. It is a fact about the address rather than a judgment about the house, and it is worth knowing which carriers are comfortable before a renewal decides for you.