TANGARAKAU STEAM 3




My Dad was a shift engineer in the powerhouse at Tangarakau. The function of this installation was to supply 400-volt direct current power for the electric locomotives operating on the 30” (762mm) gauge temporary railway serving the needs of tunnel and permanent way construction on the section extending from Tangarakau towards Ohura. Also generated was direct current at 230 volts for the lighting and hot point requirements of about 200 dwellings and business premises. A large steam engine driven air compressor delivered air to a 6½ mile (10.5km) pipeline supplying the rock drilling machines in preparation for placing explosives used in blasting out material in tunnels and cuttings.

The power house steam plant installation consisted of a Bellis and Morcom high speed enclosed engine direct coupled to its 400 volt direct current generator. Complimenting this was a vertical compound open crank engine built by Murray of England belted to its 400-volt direct current generator. These two sets provided the electric power for the 30” gauge electric locomotives. The lighting plant consisted of a Tangye single cylinder horizontal engine belted to its 230-volt generator. The large air compressor built by Ingersoll-Rand of USA was a horizontal cross compound at the steam end with a two-stage air compressor at the opposite end. The crankshaft and flywheel were at the centre of the machine. Supplying steam to these engines were two Babcock water-tube boilers sharing common brickwork, but could be and were on occasions worked independently. There was also an eighty horsepower under-fired multi-tubular horizontal boiler in its own setting. Boiler feed-water was supplied by two Worthington duplex steam driven pumps. The exhausts from all engines were to atmosphere. That from the Ingersoll-Rand, Murray and Tangye discharged into a pit with condensate drainage into a nearby creek. The Bellis and Morcom exhausted via a long overhead pipe passing about 10 feet (3 metres) high through the engine room wall to discharge over waste ground where it saturated about a fifth of an acre (0.1 hectare) of soil with cylinder oil.

Four 0-B-0 electric locomotives operated on the 30” (762mm) gauge system and collected their power via trolley poles from an overhead wire. Sidings were shunted by withdrawing the trolley poles and clipping to the overhead wire with the aid of a hand held wooden pole a lead uncoiled from a capstan on top of the locomotive. This was a dangerous looking operation in view of the fact that a man had been electrocuted by accidentally making contact with the power cable. Assisting on the narrow gauge rail was a 0-4-2 steam locomotive built by Kerr-Stuart of England. This engine bearing the PWD number 525 was a chunky looking machine weighing 8.65 tons (8.79 tonnes), had 24” (609mm) diameter driving wheels and the water was carried in a saddle tank embracing the upper half of the boiler. Its duties involved shunting the narrow gauge yard, thus eliminating the need to festoon the yard with overhead electric wires. There was much original bush surrounding Tangarakau and deer and wild pig hunting were popular pastimes. Occasionally hunting parties failed to return when expected. The powerhouse whistle would be given prolonged blasts every half-hour until the party showed up. I do not recall reports of anyone failing to home in.