When outfitted for temporary use as a mail car in early 1900, vestibules were provided and one end of the body was partitioned off, being equipped with benches, racks and sorting cases for the use of the mail clerk. About July 1, 1900, it was returned to freight service and was converted to a line car in 1902, a roof platform being provided at the time. Later renumbered 2, it remained in use as a line car until 1926.
The new combination mail and baggage car, No. 18, built by Newburyport for the EH&A in 1900, also was 20 feet long, had a simple arch roof and rode on a Dupont C truck. Constructed with vestibules, the car was described in some detail in the Exeter News-Letter of July 2, 1900:
"The new mail and baggage car of the Exeter, Hampton & Amesbury is now in service. It is vestibuled and the exterior is painted in a creamy tint, with trimmings of carmine and gold. On either side, at the top, is 'Exeter, Hampton & Amesbury St. Ry. Co.' in gilt and below 'United States R.M.S.' and 'Baggage' in red and gilt.
"The interior space is equally divided between the mail and baggage compartments. The mail room is entered from the vestibule through a massive door and is equipped with ample pouch racks of steel, a work bench and sorting compartments. A door leads into the baggage room, which has sliding doors at either side and an entrance from the vestibule. Each room has two windows on either side. The interior is painted white."
Later, the car was re-lettered United States Mail and Express and after the RPO service was discontinued in 1910, No. 18 was used for a time as a freight car and then as a general utility and salt car. As of December 1, 1911, No. 18 had two GE67 motors and K-11 controllers but by 1919, it had two motors of the Steel 34 type. The Dupont C truck was retained.
After abandonment of the EH&A, the body of No. 18 was sold and became a shed on a Hampton farm (on Exeter Road).