It was accepted by the AHJ at the time of installation, the data tag indicates the accepted load at the time. I hope you got a photo of the whole thing including the oil buffer that is a part of the assembly. I would think that after 50 years of service, its time to replace them with newer technology.
For those who might read this one day, a type c safety is an instantaneous safety (type A) with an oil buffer that provides gradual slowing like that of the type B safety (SLIDE).
If the people don't have the money to replace the safeties, how about slowing down the rated speed of the car to below 150 fpm?