An average shellac 78rpm disc weighs about eight ounces, more or less...so a milk box full (120-135 78's) weighs in at 60-65 lbs. and 40,000 at 20,000 lbs. or ten tons! Wer hired a couple of amateur "movers" when I moved the 40-odd miles from Toronto to Oshawa, Ont'o. and they showed up with a five ton cube van. That had the ROOM for the records...but not the load capacity! They had about 3/4 of the 78's on the van...which was, by then, sitting suspiciously close to the ground...and realized two trips would be necessary (or a larger truck!).
And I only have about a dozen Edisons!
However, I'm proving my house is well built (or was!). It was built sometime between 1868 andr 1874...I have about 30% of the collection in the first-floor parlour, and another 20% or so in various rooms on the second floor...and not a sign of sagging!
When I moved the collection from Illinois to Canada (1976-77) it was only about 2,000 78's (two kilorecords?), or about half a ton. I actually bought an old half-ton pickup truck specifically to move to Canada...made three trips, each time pulling a large U-Haul trailer (never did learn how to back it up!)...and there are boxes (no 78's) that haven't been unpacked since THAT move!
Note that the collection was accumulated as much for discographic research as for listening pleasure...and, as well, includes several thousand records I was given in "job lots" (couldn't argue with the price of $0.00!)...
Steven C. Barr