Barrelling/barreling along

The OED gives alternative spellings for this expression, with one 'l' or two. 'To barrel along' is to move or travel quickly and purposefully, as in a motor car. The allusion is to a rolling barrel that is perhaps rolling downhill. The expression is American colloquial dating from the 1930s. There is a hint of force or vigour in the expression, as anyone will confirm who has tried to control a runaway barrel rolling downhill.