"There were certainly FAR MORE cars than FGE/WFE/BRE with roller bearings before 1961,
which is the period of the list (1900-1960)."
December 12, 1958 tally was; 31,865 railroad owned cars and 6,555 private cars equipped with roller bearings. The total of 38,420 cars represented less than 2% of all freight cars in 1958. As of June, 1959, an additional 12,000 plus cars had been ordered equipped with roller bearings.
"Some cars you would not expect to, got roller bearings. For example, the Great Northern
and CGW purchased coal hoppers in 1957 with roller bearing trucks."
Hopper cars dominated the railroad owned car types with a total of 13,145. GN had 797 and CGW had 175 hoppers with roller bearings. ACL was number one with a total of 3,580 followed by WM with 2,454.