Well, 'ATC' isn't ambigous in Sweden. In Sweden, there is only one ATC, and it will never be mixed up with japanese or bulgarian ATC.
And the system IS called ATC, signs along the track say "ATC begins" or "ATC ends" or similar, documentation for drivers etc say ATC, documentation on the Trafikverket website says ATC. ATC everywhere, never Ebicab. So it would be fairly confusing to tag the railways with something "no one"* has heard of. Because of this, I do NOT vote for changing tags in sweden from ATC to Ebicab. If something has to be changed, then ATC-SE is a better choise.
*) Of course, someone has heard of Ebicab, but not the majority of people interested in railways.
Why should it be called Ebicab i Bulgaria? Good question. I have no idea. Perhaps it is actually called "Ebicab" there? I don't know.
/Tomas