This article is incomplete.
One of the claims made for the Fairlie's Patent locomotive was reduced "oscillation" whatever that is.
Steam engines have unbalanced wheels because of the driving and coupling rods. This is one kind of oscillation. Counterweights can balance out the top-down hammer blow, but this causes forward-aft jerkiness. In practice some counterwieghts are provided so that there is some hammer-blow and some jerkiness.
- "THE FESTINIOG RAILWAY". The Hay Standard And Advertiser For Balranald, Wentworth, Maude.. (89). New South Wales, Australia. 16 April 1873. p. 2. Retrieved 22 April 2017 – via National Library of Australia.