. . . I am guessing that one of the reasons this type of power "tamping" did not last is that the ballast was really not compacted all that well directly under the tie, is that true?
. . . It depends on the type of ballast, and the amount of raise. The Pullman seemed to work OK at stuffing cinders, small gravel, oak leaves and branches under the ties, but it wouldn't move good rock ballast to where you wanted it. That's why it was being used on the yard tracks in old Selkirk.
By the way, the "Oak leaves and branches" is a direct quote from John Flannery, Track Supervisor at Minerva, OH in 1966. We had a gathering in the Division Engineer's Office in Cleveland one Sunday night, while we were waiting for No. 6 to take us to Albany for the annual Maintenance of Way Seminar at Jug End Barn in Mass.
Frank Diego, at Marcy, had a gon full of what he said were "Oak leaves and branches." He was wondering what to do with it, because the LE&P had just been taken out of service and we had no access to Gateman's Dump.
John Flannery said, "Send the car to Minerva. We use that stuff for ballast." Such were the good old days.
By the way, the gentleman who organized those seminars, which were very useful for all of us, told me that he started on the New York Central setting stakes ahead of a Pullman Track Ballaster on the Michigan Central. After that, he served as an Artillary officer in WW II, so the Ballasters were around before 1945, at the latest. Larry B knows of whom I speak.
I have a 1937 Maintenance of Way Cyclopaedia, which shows nearly every M of W machine available at the time, as well as most types of track material. The Pullman Ballaster isn't listed or advertised. Pullman-Standard had a pretty good advertising budget, so if it's not in the book it didn't exist yet.
GAD!