proving ground

plural proving grounds

1. governmentA terrain or installation for testing weapons, military equipment, or tactics.
2. figurativelyA venue or project in which new technologies, methods, or techniques are tested.

   Several design issues emerged quite quickly with the Mirrlees engine, and so these locomotives can be seen as its rail-traction proving ground.

   2021 June 30, David Clough, “Brush: a UK rail icon”, in RAIL, number 934, page 55

   1 more example

   To test the new equipment and vehicles that will work to the high voltage a.c. system, a proving ground was sought at a convenient point, and the lines from Colchester to Clacton and Walton have been selected.

   1956 June, “Electrification in Clydeside and East Anglia”, in Railway Magazine, page 414

   Synonyms: testing ground