/t/ and /d/ in tr- and dr- Initial Blends

When a syllable begins with tr- (e.g., tree, train, travel) the initial stop consonant /t/ can be retracted by the following /r/ and begin to sound more /t͡ʃ/-like. So, the initial consonant in "train" may resemble the initial consonant in "chain". This change in pronunciation, however, indicates an allophone of /t/ in this context, not a substitution for the affricate. This tutorial examines this along with a similar phenomenon in dr- words.