"Gangbusters" has become a sort of generic intensifier but the original phrase was something like "to come on like Gangbusters", referring to a radio show with

"Gangbusters" has become a sort of generic intensifier but the original phrase was something like "to come on like Gangbusters", referring to a radio show with an obnoxiously-noisy intro (it's on Youtube if you're curious). Increasingly distant metaphorical use and people falling out of familiarity with the origin of the phrase led us to modern constructions like "my tomatoes are going gangbusters!" which don't really fit with the original usage.