Allen Hazen wrote:About that Q-2 book mentioned in my previous post...
(3). Also included, some internal documents, including a letter from a P.R.R. purchasing agent to Alco, enquiring about the royalties Alco would want for seven lateral motion devices. (That one surprised me: I had assumed that the devices themselves were manufactured by Alco, and that any patent royalties would have been included in the price...) Explaining that "Because of some design details, only 7 of the American Locomotive Company devices will be used; the remaining 3 will be a Pennsylvania Railroad design."
The Alco LMD itself probably could not be copied directly without patent infringement, but that did not preclude other designs. As far as I know, Franklin offered an alternative design, but it does not seem to have been much used. Evidently there was enough “wiggle room” between the patents for PRR to design its own version.
Strange nonetheless. How the 7 Alco and 3 PRR units would be distributed is unknown, but however it was done at least two axles would have each had a pair of Alco units, and at least one axle would have had one Alco and one PRR unit. Maybe there were space constraints and the PRR unit was dimensionally a better fit in some locations? If that situation obtained, that the Alco unit was applied where it fitted suggests that it was viewed as the better of the two.
There is a picture of the Alco device at: https://www.facebook.com/NashvilleSteam ... 230215746/
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But the accompanying explanation can’t be right, as a feature of the device was that there was no lateral spring pressure on the axleboxes when a driving axle was centred with respect to the frame. Rather when the axle moved laterally, the axlebox moving inwards contacted the spring and started to compress it. The other end of the spring (or really two springs separated by a collar) could not move proportionally, as it was effectively up against the frame.
Patent royalties may have been worked out on case-by-case basis with some kind of sliding scale, perhaps to keep this aspect at “arm’s length” from pricing deals that might have been subject to ICC scrutiny.