The speed of cleaning up a derailment depends on many factors. If there is access and room, and the mainline has high traffic with no easy detour available, it is often better to just get the track bed cleared and reopen the main. Unless there is haz-mat or some high value cargo, it may be cheaper for the railroad just to pay the claims.

You ought to see a wreck with aluminum body coal cars - they fold up like crushed soda cans and the railroads don't even try to rerail the cars because if they have more than minor damage they are not worth repairing, so they just shove them to the side, salvage the trucks and brake valves, crush them with an excavator and haul them out by truck to the scrapyard.

I've been on various shortlines where we would spend a week cleaning up a half dozen derailed cars in an effort to salvage the load and sometimes the cars remain repairable. I've also had several loaded grain cars roll over onto the BN main pulling into the year - Hulcher had the track open in less than 16 hours. The sidebooms just picked up the grain cars and carried them off to the side. After the grain was salvaged, the cars were eventually scrapped due to twisted center sills.