i stepped into the way back machine and remember PC trains ny-6 and sw-6 out of E St Louis back around 68-69 averaged nearly 100 cars with 5 to 6 thousand tons. very few long cars on these trains except for auto racks and they were mostly loads. sometimes an empty car for a new england or east coast connection might sneak in but not many. both trains carried a perishable block on the head end and those were not very heavy cars. i think what got the average weight up was a lot of wet and dry chemical traffic in tank cars and covered hoppers. these trains did not carry open loads other than autos.
other east bounds would have a higher percentage of empty cars and some 100 car trains only figured out to 3 or 4 thousand tons. this was back when the old wooden axle PRR car reporting system was in use and the yard clerks got their tonnage off the way bills and used an arbitrary figure of 22 tons for light car weight.
grizlump
FreightCar America which began in Johnstown a century ago has its specs published (BethGons, etc.) for every railcar.
Conemaugh Road & Traction circa 1956
I think those are just the 'payload' weights - for the 1990's car weights, that would be 130,000 lbs. - with a 60 or 70,000 lb. car it would total 200,000 lbs., and that's about right - maybe a little light - for the early years of that decade.
Allowable gross weight for freight cars of 263,000 lbs. = 131.5 tons is pretty nearly standard and universal now. Actual and average gross weights can be considerably less - not only for empties, but for light loads such as auto-racks/ multi-levels, auto and truck frame cars, special loads such as appliances and some auto parts, etc.
Many cars and routes are good for 286,000 lbs. = 143 tons, esp. coal and grain trains.
The current 'outer limit' is 315,000 lbs. = 157.5 tons on 4 axles. There's not many of those due to the potentially ruinous effects on rail and costly upgrades to bridges, esp. for short lines - but they're out there. There was an article in Trains a couple years ago about that.
- Paul North.
The current 'average' empty weight varies from 25-30 tons(50' box cars vs covered hoppers). The payload capacity of that box car can vary from 50-70 tons. The covered hopper payload can vary from 100-115 tons. That box car may not be loaded to maximum capacity, and I would suspect the average payload to be 40-50 tons(your example is very close). So the total weight will be about 70-75 tons. On the other hand, grain hoppers are usually loaded to the maximum and will have over 100 tons of product in them - 130 tons total weight. Averaging coal cars/grain hoppers/box cars/etc may get you something like that 65 ton number. And we have not even factored in 'empty' cars....
Jim
Modeling BNSF and Milwaukee Road in SW Wisconsin