Jeff Livingston in his book
Oahu's Narrow-Gauge Army Rail has some of these pictures and others. And he tells us about the equipment and the event.
The rail artillery and locomotive is from the 41st Coast Artillery unit of the U.S. Army and was part of the defense of Oahu in the 1920s and 1930s. This unit started out in 1922 with 12" mortars and then received 8" guns in 1934. The locomotive is from 1926. The unit was assigned to Fort Kamehameha at the entrance to Pearl Harbor.
In September 1935 the Army staged a military review at Schofield Barracks for the visiting military subcommittee of the House Appropriations committee. To allow the 41th Coast Artillery unit to be included in the review a temporary track was laid at the Scholfield Barracks parade grounds.
Jeff Livingston has done two books published by Arcadia Books about military railroads on Oahu. The other is about the Navy at Pear Harbor.
Brian Norden