The last two trolleybus routes were 48 and 48b, as you can see in the maps you posted.

48b was a short version of line 48 that only ran to the Constanța railway station.

Thanks, I've mentioned this a number of times in my other comments. It is that routes 48 and 48b are often perceived as the same service, with 48b been a supplemental short turn variant. I've edited a description under the photo, nevertheless.

By the way, on the day of my visit route 48b did not operate at all.