Equalization due to over stiff springs or not I can hear the difference between sprung and un-sprung locomotives (steam and diesel) running through a network of crossovers on my railroad. The un-sprung ones (especially china drive diesels and MTH 3-2 locomotives "thunk" as they pass over my R-O-W smoothly laid frogs. The difference in sound is amazing - and distracting.
As far as tractive effort I found that a heavy MTH N&W J could pull 20% fewer passenger cars than a lighter and longer wheelbase sprung Sunset T1 on my 2.2% super elevated Horseshoe Curve. Pretty sad given the well know results when the N&W and PRR swapped locomotives for comparative tests in the 1940's..
