For instance, the original Sumpter Valley was a Rail
way and remained such for it's entire existence. But when the restoration was organized in 1971 that name was still owned by someone, so Sumpter Valley Rail
road was adopted. (Actual corporate name is Sumpter Valley Railroad Restoration Inc.) Much later we were able to acquire the original name and now use that on all original equipment, although the official name is still SVRR. That sort of confusion was common in the early days of railroading.
BTW our reporting marks are SUVX, though that only appears on official FRA reports.