go gangbusters proceed very vigorously or successfully. North American informal
☞ Literally, a gangbuster is 'a person who assists in the vigorous or violent break-up of criminal gangs', from which the more general sense of 'a successful person' has developed. The phrase like gangbusters means 'vigorously and successfully'.
2012AndrewThe 4th Avenue Blues The railroads have been going gangbusters lately with lots of tonnage to haul as the economy revives.