The idea of tachyons didn't come out of any sort of research.
I take it you meant
experimental research, as opposed to
theoretical research employing ‘thought experiments’.
That’s an interesting distinction, as most of Einstein’s seminal papers fall in the latter category, the experimental underpinnings of which (to the extent available) were provided largely by others who produced the supporting observations. In several respects, that’s an ongoing endeavor.
All of this is not to say that I really think FTL is possible, to the contrary. Given current understanding it’s highly unlikely indeed, but also not yet conclusively and unambiguously disproven, and hence incredibly intriguing. And since it's hard if not impossible to prove a negative, it'll probably remain that way for some time.
