These cars have a couple issues regarding “fire” concerns. (1) in any brand of passenger car where the two pickup rollers are bridged internally to avoid flicker on switches, there is the possibility of a short should either roller come to rest on an outside rail in a derailment. If the wire gauge is sufficient, it will just get very hot before tripping a breaker (if there is one). My K-Line cars (28) had very light wiring so that the wire would char and need replacement. The first time it happened, it was of course in a diner car (grease fire in the kitchen? . . . great amusement at the club). (2) K-Line’s foreign assemblers were notoriously stingy with their wire and often didn’t supply sufficient slack to allow free truck swivel. This could cause the wire to be cut through by the very sharp edges of the light bulb openings in the grounded metal floor. Rewiring is a good idea in either case.
To ease concern, you would be blessed with ample quantities of shmoke und Shtink, and cut the power long before orange flame might present. I have always loved these cars and have considered them well worth any effort to re-engineer their electrical shortcomings.