I guess you need to give little more background information about the title. For example, is the engineer responsible for managing equipment, or making equipment? Does "主任" mean he is in charge of the equipment (making or maintenance), or he is in charge of managing a bunch of engineers who make or manage equipment?
Google's translation:
主管(电力,机械,暖通,给排水等)设备专业设计的主任工程师 ==
Is in charge of (electric power, machinery, warmly passes, for draining water and so on) equipment specialized design chief-engineer
babel fish translator (http://babelfish.altavista.com/tr)
主管(电力,机械,暖通,给排水等)设备专业设计的主任工程师 ==
The manager (electric power, machinery, warmly passes, for draining water and so on) equipment specialized design chief-engineer
Are you sick? everything is clear already! My answer is come from a interview chance sent by a engineering company like you mentioned, and also you can find out it on some jobbank websites. jzhang77's anwer is also no problem for any of your translation about that. Please do not waste your time and trouble somebody for nothing.