[1][2] In 1857, the two visited Britain and France to study the rail system and compiled a report for the presidents of American railroads, The Permanent Way published in 1858.

Holley's most famous book, A treatise on ordnance and armor published in 1865, followed a visit he made to Britain in 1863 when he again met Zerah Colburn.

Ten of those fifteen were for improvements in the Bessemer process, for which he purchased the US rights in 1863 on behalf of a consortium of investors.

[1] In 1882 he was awarded the Bessemer Gold Medal of the British Iron and Steel Institute for his services to the industry.

He received many honors, including being made an honorary member of the American Society of Mechanical Engineers in 1892; and in 1890 a monument was unveiled in Washington Square Park, New York bearing a bust of him.