Possibly daft questions, but I'll ask anyway .... are tank locos, designed to operate regularly in either direction, any better or worse than tender locos in this regard? .... and .... are any particular designs known as firethrowers, or include additional features (or geometries) which minimise the problem? Indeed. I recall Tom Rolt mentioning an incident when Dolgoch (which apparently had nothing resembling a proper ashpan at that time) vomited the contents of it's firebox onto both it's own valve eccentrics and the "two foot" as a result of hitting a particularly manky (by Talyllyn standards of the era!) rail joint.