I bet you didn't even know there was a rail service running from Nelson to Blenheim! Let me tell you about it.
In 1876 railway construction was started in Nelson. It was intended to join to the West Coast, but only ever connected as far as Kawatiri, a distance of 103 km, some thirty-six years later. While initially profitable, by 1955 the line was closed, despite numerous protests, petitions and sit-ins. 1957 was election year, and in an attempt to maintain the Nelson seat the government promised to complete a survey of possible northern routes to Blenheim and review other possible routes to the West Coast. A decision on the link would be made then. In the meantime the government would subsidise passenger and freight charges, so that they were charged at rates as if a railway already existed. The Nelson to Blenheim route, charged at railway rates, but contracted by buses and trucks, was designated in law as a "notional railway" and a number of specific stops as "railway stations".
The problem was that the service was successful. Where a railway would see increased patronage as increased profits, the government saw an increased expenditure in subsidies, or in other words, increased losses. In the first year subsidies cost the Railways Department ₤105,000. In 1979, when the subsidies were finally repealed, the annual payout had risen to $10M.
With the passing of an enabling law, the Nelson to Blenheim railway, the one with steel rails, broke ground and started winding its way to Blenheim in 1960. However, the Labour government of the day was voted out that same year, and the incoming National government promptly killed the enabling legislation, which ended all hopes of a real rail line. During that time only some formation had been built - no steel rails had actually been laid.
As the Nelson to Blenheim line was only a notional line, serviced by buses and trucks, with no actual railway, this cache is the only cache placed on the line, representative of the entire railway.
I could not find where the designated "railway station" was, however I suspect there would have been two locations, for general freight and for passengers. The published coordinates take you to a representative rail station, the town's main bus stop, and the final is less than two kilometres away, on a mostly decommisioned section of the notional railway. To get to it shoot off on a bearing of 292° for 1492 metres. You can drive right to the cache.
References:
wikipedia.org: "Nelson–Blenheim notional railway"
wikipedia.org: "Nelson railway proposals"
wikipedia.org: "Nelson Section"
Supporting the GeoKids program - my caches have treasure, makes them fun for kids to find!