The script AI rail (https://forum.simutrans.com/index.php/topic,20188.0.html) contains the following texts for translation.
#________________________________script_ai_text_________________________________
#________________________________script_ai_text_________________________________
%s build additional convoy to line: %s
%s build rail line from %s (%s) to %s (%s)
%s build road line from %s (%s) to %s (%s)
%s build ship line from %s (%s) to %s (%s)
%s extends the route from %s (%s) to %s (%s)
%s optimize way line from %s (%s) to %s (%s)
%s removes convoys from line: %s
%d convoys of the line %s were retired
You can post the translated texts here or use the translation page (https://simutrans-germany.com/translator_page/base_text/index.php?obj_id=88619&lang=en&ref_lang=none&trans_lang=en,fr,es).