Block on street possibly encloses new access for passengers (7)
I believe the answer is:
gangway
'access for passengers' is the definition.
'gangway' can be an answer for 'access' (thesaurus). I am unsure of the 'for passengers' bit.
'block on street possibly encloses new' is the wordplay.
'block on' becomes 'gag' (I am not sure about this - if you are sure you should believe this answer much more).
'street possibly' becomes 'way' (street is a kind of way).
'encloses' indicates putting letters inside.
'new' becomes 'n' (common abbreviation eg NT for New Testament).
'gag'+'way'='gagway'
'gagway' going around 'n' is 'GANGWAY'.
Can you help me to learn more?
(Other definitions for gangway that I've seen before include "Temporary bridge for getting on and off a vessel" , "Aisle between seats" , "Movable bridge from ship to land" , "Way to board ship" , "means to secure passage on ship" .)