The New Zealand Railways Magazine, Volume 3, Issue 1 (May 1, 1928)
Mercer (43 miles), named after a Royal Artillery captain who fell mortally wounded in the storming of Rangiriri, was originally called by whites Point Russell after the Auckland politician who was Minister of Defence in 1863. The Maoris have adopted the name in part, and to-day call it Te Paina (“The Point”). Mercer is a shipping port as well as railway station. River steamers trade down to the Heads and upstream as far as Cambridge, sixty miles away. In the days when it was the head of the iron way travellers to the Waikato took passage here for Ngaruawahia and farther up by the paddlesteamers that went steadily flapping their way up against the strong river. Some of these early days steamboats traded up as far as Alexandra, on the Waipa River. Preceding this peaceful passage era was the military period, 1863–66—the three years during which British regiments occupied the conquered Waikato.
A relic of those times stands near the river bank to-day—one of the two iron turrets or cupolas of the armoured gunboat “Pioneer.” This circular turret, with its apertures for rifle fire and its embrasure for a gun, now forms the foundation of Mercer's memorial to its soldiers who fell in the Great War.