Tell engineers strange tale (6)
I believe the answer is:
relate
'tell' is the definition.
(relating is a kind of telling)
'engineers strange tale' is the wordplay.
'engineers' becomes 're' (Royal Engineers).
'strange' is an anagram indicator.
'tale' is an anagram of 'late'.
're'+'late'='RELATE'
(Other definitions for relate that I've seen before include "Tell; connect" , "Tell - the marriage guidance people" , "Make a logical or casual connection" , "Narrate or associate" , "Tell in Tralee" .)