Rail Car Causes Derailment-Who pays

While watching trains recently I thought of this question. If a car owned by tilx or whoever is found to be at fault who pays for the clean up? Would it be the railroad or the car owner?

Too hard to answer because too many factors to list. Derailments are caused by many things: truck "picked" a switch, worn or flat wheels (badly enough), trainman error, other mechanical defect. Most of the time, cars are inspected regularly to prevent problems. If a defect is found, it goes to the RIP track for repair, or set out for car peck to fix on-scene. I won't attempt to solve this one.

GF

The railroad on which the derailment or wreck happened bears the cost of clean-up, damage to cars owned by other railroads or private car lines or shippers, damage to non-railroad property, personal injuries if any, fire and police department involvement, etc. The railroad handling the car at the time of the derailment or wreck accepted the car that caused the wreck; the equipment should have been inspected before being moved. If it is a design defect like you get with motor vehicle recalls it might be another story. I handled lots of derailments and wrecks when I was in the Boston & Maine Finance Dept. 1968-86.

The railroad is still responcible, even if they have a car derails with a mechanical defect, the fact remains they(the host railroad) accepted the car in Interchange.
as far as repairs and cost of defective cars those rates are found in AAR interchange rules.
The Host railroad has their car inspectors inspect and accept the cars in interchange, and that is last defence to stop a defective car.