[1] Fiddle yards were first built by British modellers so that they could build small layouts and operate them in a realistic manner.
[4][5] This was an urban passenger terminus that led directly into a fiddle yard, hidden beneath a locomotive depot above it.
Denny also used it to rotate by half a turn and to reverse the trains wholesale, without needing to uncouple and move locomotives from one end to the other.
Denny was noted for his use of non-railway mechanisms and the original was cranked around by a Meccano geared drive, with remote switching and monitoring by a row of sprung metal contacts.
Fiddle yards can also contain a balloon loop for turning entire trains, usually in conjunction with a fan or traverser design.