This move to the west side of the railroad was being resisted by many townspeople, especially Joseph M. Haywood, through editorials in his Ambler Gazette. Most of Ambler's homes were on the eastern side of the tracks, as were its schools and churches. One exception was Trinity Mission, meeting in a room in the Opera House building. They would eventually move into their new Trinity Memorial Episcopal Church, being erected by the Mattisons in memory of their deceased daughter Esther Victoria.

Buchanan and Mattison made numerous trips to Washington, meeting with the Postmaster General's office, in an attempt to have the Ambler office moved to Mattison's structure. Because so many lives had been lost at the dangerous crossing, there was much opposition to moving the facility across the tracks.

The next thought was to interest a group of investors in erecting a structure on the east side for exclusive use of the post office. Three prominent individuals met, agreeing to construct a building next to the First National Bank on property owned by George K. Knight, whose son Alexander was one of the three investors; Joseph Haywood and John J. Houghton were the other two. The group met with the Postal Department in Washington, getting their commitment to lease the planned building for a ten-year period.

Design for the proposed structure was presented by Ambler builder J. Sims Wilson, and was described as being "of one story in height, of Colonial style, following the Ionic design in architecture". With approval received from Washington in September, Wilson began construction immediately, promising completion within a month. Earth taken from the excavation was hauled a short distance to Spring Garden Street, being utilized to raise the level of the roadbed over the creek. Millwork for the new post office came from a plant in North Wales, while bricks used in the structure were manufactured locally on South Main Street, at the Ambler Brick Works of the late Irwin Dager. His widow Mary Dager was continuing operations, with kilns capable of producing 100,000 bricks per run.

A striking feature of the new building was the front elevation, dominated by its four galvanized iron columns. Ambler painter Ellsworth Niblock completed his work inside and out by Fall, enabling Postmaster Buchanan to conduct business before the year's end in the new post office, which was considered by many one of Ambler's handsomest structures.

John Buchanan was to be remembered for implementing home delivery of mail in 1902, the first two letter carriers being William W. Slutter and Clarence Streeper. John was postmaster from 1898 until 1904 when illness forced him to resign, with his brother Joseph A. Buchanan succeeding him. The illness was so severe that John died early the following year at 43 years of age, the death occurring on the birthday of his brother Joseph.

With original roof lines unchanged, the old post office is visible today as the renovated two-story building next to the former Mellon PSFS Bank building on Butler Avenue. It has been joined to the building originally known as the Knight Building.

Accounts of the post office history in recent years have shown that it at one time occupied one of the stories of the Ambler Opera House building. Personal research fails to verify that information.