The line was extended from
Penrose to Mercer on 20 May 1875, though the pioneer British contractors,
John Brogden & Sons, ran an excursion train the day before.
The New Zealand Herald said, "
This will be a busy station for some time to come, it being the terminus." It described the route as crossing
Mangatawhiri swamp, then running beside the
South Road, with a short branch line being constructed to connect with the Waikato Steam Navigation Company's (WSNC) boats. It said the station and other buildings were still being built. 'Some time to come' ended just over 2 years later, when the line was extended to
Ngāruawāhia on 13 August 1877.'''' The service began with two trains per day each way between Auckland and Mercer taking 2hrs 50mins. The station was unfinished when the railway opened.
Refreshment room The
refreshment room was built by 10 August 1877'' and extended in 1878/79 for £180. An 1880 advert for reopening of the refreshment room said trains waited 20 minutes. Until New Zealand Railways took over in 1917, the Mercer Railway Hotel, opposite the original station, managed the refreshment room. The hotel was rebuilt in 1898, with 15 bedrooms, 3 sitting rooms and a 50-seat dining room. The refreshment room gained importance when dining cars on main trunk expresses were removed as a wartime measure. The refreshment room was the target of poet
A. R. D Fairburn's, with his famous quip. "The thought occurs to those who are entrained: The squalid tea of Mercer is not strained." Sit-down” meals were discontinued from 13 December 1923. From 1940 a hostel accommodated female refreshment room staff. On Tuesday, 28 October 1958 the refreshment room closed, following the introduction of railcars. It had employed 4 to 12 staff.'' the station area regularly flooded, including in 1906, 1907, 1917, 1924, 1925
1879 station The original station burnt down on 19 May 1879, due to an old stove in the refreshment room. A new station opened on 4 October 1879. In 1883 a plan was made to re-arrange the station. By 1884 there was a
special station, platform, cart approach, x goods sheds and another of x for WSNC, loading bank, crane, water, coal,
turntable, wagon turntable, engine shed, fixed signals, stationmaster's house, urinals and a
passing loop for 50 wagons.'' after the 1879 station was also destroyed by a fire begun in the refreshment room, on 23 December 1900. A temporary station was formed from 5 huts, which had housed prisoners at
Rotorua.
Goods In 1889 provision was made for loading sheep and in 1890 cattle yards and in 1896 sheep yards were added. By 1911 the
goods shed had been extended to x .
and improvements were made in 1908, 1916 and 1919. By the time of the 1907 flood the station had further tilted. By 1956 its floor had a 1 in 12 slope,
In 1907 Mercer was one of three stations in the Auckland Section to get a larger turntable, the others being Rotorua, and Taumarunui. A Wellington to Auckland "Limited" express derailed on 28 October 1940 killing the driver and fireman and injuring 12 passengers. An estimate put the speed at 75 mph (though some at the inquiry gave evidence of normal speed) on the 8-chain radius curve, just south of the station, near the former tunnel opened out in 1937. The engine,
K900, tipped on its side and was overrun by six carriages. Removal of the tunnel allowed double tracking and easing of the speed limit to . The curve has been greatly eased in the 2006 Mercer to Long Swamp Expressway 4-laning of 12 km of
SH1, which included this 1 km of rail deviation. Another derailment at Mercer was on 3 September 2013, when a freight train blocked both the road and railway. at Mercer == Mainline Steam depot ==