While the payload of an 85 foot heavyweight car weighs a lot less than the payload of a modern box or hopper car, the overall weight of the heavyweight cars was, in many cases, greater. Heavyweight cars were ballasted with poured concrete floors, and their total weight could run to well over 65 tons, especially dining and tavern cars that required exceptional stability for passenger comfort. Sleepers and coaches generally ran about 65 tons.
The reason for this is that the technology of trucks was relatively undeveloped in comparison to modern passenger trucks. The only way to stabilize the cars and make them comfortable riding was to weigh them down and meant that 12 wheels were needed to support the weight. Improvements in the riding qualities of the trucks were what made lightweight cars, streamliners, possible, because the cars could be made lighter but still ride comfortably. Standard suburban, or commute, cars, on the other hand, did not make particularly long runs, so the passengers could tolerate the rougher ride that these lighter cars, around half the weight of the long haul heavyweights, provided the passengers. Big difference between riding for a half hour or even an hour and riding for three days.
I've ridden both types of cars, commuting for years on standard suburban cars and riding several times on heavyweight Harriman coaches in my younger days and the difference in ride was remarkable.
Bernie
Edit: It occurs to me that my memory of the weight I mention, 65 tons, may be off a bit, but the principal was that the heavier the car the smoother the ride. The tare was many times the weight of the payload and the extra wheels were required by the overall weight.
