[7] The M7 was built as two separate but similar models due to the different electrical and signaling systems on the LIRR and Metro-North.

Other, more minor, aesthetic differences include illuminated number boards, present on the M7 but absent on the M7A.

In late 2006 the MTA began a replacement of all M7 armrests after paying out over $100,000 to customers who filed complaints.

Metro-North's management received feedback about the M7, which influenced the development of the M8 railcars for the New Haven Line.

In the fall of 2006, the M7As started to experience serious braking problems due to foliage on the right-of-way, a condition known as "Slip-Slide."

[9] On April 19, 2021, the LIRR proposed equipping two pairs of M7 railcars with batteries for travel in diesel territory, pending feasibility studies.