Heavy weight passenger car question...

Can someone tell me what year heavy weight passenger cars came out and what year they were replaced by more modern cars ?. I’m sure the latter part of the question will vary from railroad to railroad.

Thanks in advance.

Tracklayer

The New Haven had the first lightweight and air conditioned cars in New England in 1934 with its Pullman-Osgood Bradley lightweights.

The classic steal heavyweight cars started making their appearance in the late 1800s. Eneugh had been built that when the 20th Century Limited started in 1904. It was with steel cars.

The heavyweight cars stayed on in first class passenger service (Though usually in second or third string trains and as cars for second and third sections into the early 60s. though It took till the advent of Amtrak for all heavyweights to be retired. Many found second careers in MOW trains.