They did not commonly appear on freight railways until the 1960s, when the modernising British Rail system introduced merry-go-round (MGR) coal trains that operated from mines to power stations and back again without shunting.
European systems were almost universally converted to looped operation in the early 20th century, and most also adopted single-ended trams.
[citation needed] Loops were also used on some tramways in Asia, South America and New Zealand, as well as on other Australian systems in addition to Sydney.
Occasionally, balloon loops are used for reversing trains on lines with heavy grades and tight curves to equalize wear on both sides of locomotives and rollingstock.
Such a balloon loop was constructed at Beech Forest on the 2 ft 6 in (762 mm) Victorian Railways line from Colac to Crowes.