Who to contact when handling editor is anonymous and manuscript is delayed? Here a question has been asked about the ethical grounds for an editor to be anonymous from a reviewer point of view. I am facing similar problem but being an author my concerns are different. I have submitted an article to a prestigious Elsevier journal. The article went through two revisions, one major and one minor, and still under review. During all this process the handling editor never showed his identity. Currently I am facing unexpected delay in review process (5 months after minor revision). I want to send email to associate/handling editor but whenever I send email via Elsevier system I receive an unsatisfactory response from journal manager not from editor. I am not sure if he/she is seeing my emails. Is it an appropriate approach for associate/handling editor to hide the identity from an author? Is it appropriate if I write email directly to Editor in Chief? if yes, then how should I compose my email?
Is it an appropriate approach for associate/handling editor to hide the identity 
  from an author? 


This question has been discussed extensively in the question you linked. Whether it's "appropriate" is a difficult question, but it's not entirely uncommon and I am not sure why it would be an ethical problem. Personally, I prefer transparency over information hiding, but there are definitely arguments in both directions (and most of the time it probably simply does not matter).


  Is it appropriate if I write email directly to Editor in Chief?


Sure, why not? 5 months is a fairly long time for a minor revision, and sending an email to a person concerning an official role that (s)he voluntarily took over seems almost always ok. Whether this will change much is a different question, but it's worth a try.


  if yes, then how should I compose my email? 


Short and respectfully. Avoid being combative, avoid assigning blame, and don't ask who the handling editor is so that you can bug her or him yourself. Briefly state that you have submitted a minor revision for the manuscript XXX on date YYY, that you are wondering what the cause of the delay is, and want to inquire whether a notification date can already be foreseen.