An example of the initial variant of the famous Rivers Silver Streak 2.5 cc (0.15 cuin.) diesel from England. Introduced in March 1959, the Silver Streak was manufactured thereafter in several distinct variants. Current estimates are that perhaps 900 examples of the initial variant were produced before a switch was made to the more powerful and more robust Mk. II version, which appears in the right-hand supplementary image below. The engine achieved considerable competition success for a time, most notably during the 1960 season, but was unable to keep pace thereafter with the ever-improving Oliver and ETA opposition. All Rivers manufacture ceased in late 1963, apparently as a result of a financial crisis of some sort.
For more information on the Rivers range, see my in-depth two-part article to be found on the late Ron Chernich's "Model Engine News" (MEN) web-site.