Going back a long way (to when I was a teenager in the late 1960s/early 1970s), Foden and Commer trucks and buses used 2-stroke diesels of their own design. In fact the
Commer TS3 engines were derived from the same Jumo aero-engine technology as the Napier Deltic, being opposed-piston 2-strokes.
The GM (Detroit Diesel automotive and EMD rail/ship) two-stroke families started life with the Winton Engine Company, which (along with the Electro-Motive Company) were bought by GM in 1930 and effectively merged together as the 'Electro-Motive Division'. GM had been working on 2-stroke diesel designs, but decided they would get to market faster by buying expertise from someone else, so they 'bought the company' and the rest is history...
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I quite like the noise the 57s make (it's better than the 66s) and yes, the Irish 071s are much closer to a proper EMD 645 engine 'sound' because they have less silencing.
But if you want a comparison with the 'real thing', enjoy the noise of four V16 645-E3 at full throttle (from 01:35 onwards) here -
https://youtu.be/4u5Np9zl4TE
[youtube]4u5Np9zl4TE[/youtube]
(If you watch from the beginning, the loud squealing/screaming noise as the two GEs go past is 'controlled wheelslip' in action on wet rails. The EMD pushers also slip a little in the same place - just to show you they are working hard lifting maybe 15,000 tons of train up the hill

. The people on the footbridge were a group of enthusiasts from the UK enjoying the show - I just happened to be there at the same time).