Thursday, 9 April 2015

Early NIMT Improvements Manawatu [2]

Last time in this blog I looked at the realignments that were done around 1915 between Kakariki and Greatford. This was not the last of the changes to the line between the two stations. The works that were addressed then were the easiest to achieve over fairly short distances and without too much earthworks. What we do know is that in the late 1930s, specifically 1936/7, there were two large projects started to improve the line between the stations again after almost 30 years experience of NIMT operation and 20 years since the previous improvements.

The first of these projects as far as I can determine at this time was the improvement of the section of railway between the Rangitikei River and Greatford township.  In this area the railway encounters a notable gradient which can be very roughly quantified by the rise in altitude from Kakariki (70 metres) to Greatford (105 metres), which when averaged over the track distance works out to an average of 1 in 137. But within that area there could easily be a lot of variation and perhaps a better indication is over a short stretch of the route where the line crosses the 80 metre and 100 metre contours quite close together, which is indicated to occur over a relatively short distance of 1 km or less and therefore suggests that in that short stretch around a 1 in 50 gradient is reached. The old line being apparently lower meant this grade could be greater, or over a longer distance, probably a steeper climb overall featured as the old route appears to be at a lower level.


Although we don’t have total certainty of where this is, it is quite likely that it is at the big 90 degree curve where the main road diverges and cuts across to its intersection with SH1, as the bluffs which can be seen above are probably those which are seen alongside the highway in this area. This is the area known to railwaymen as the Kakariki Bank and the use of the long sweeping curve indicates the desire to spread out the ascent/descent. Since there is not a substantive change in the route overall we can only assume that in this instance the new embankment may have made the grade more even and therefore eliminated one or more sharp peaks or dips in the previous alignment. The newspaper article also mentioned  the objective of eliminating a level crossing, where a small overbridge can be seen opposite the siding into the ballast quarry. The route shown is approximate but is probably the most likely one apparent on GE since the maps are somewhat ambiguous.


The second improvement of the late 1930s was the replacement of the Rangitikei River bridge just north of Kakariki. This being a road rail bridge, it was a period in which many such bridges of this type on busy routes were being replaced. Road traffic had increased greatly in the lifetime of many of these bridges; even though the one at Kakariki has never carried any state highway, it is part of an important secondary route through to Feilding. Unless the bridges had gatekeepers present, trains often had to be slowed to 10 km/h when crossing such bridges, and as the bridge was at least 35 years old, it may have needed repairs or strengthening. Although this bridge was started at the same time as the realignment works and was linked with them in one newspaper report, there does not appear to be any real connection with the realignment because the new bridge was at practically the same height and alignment as the old one.


As we can see the old and new are very close together and some traces still exist today of the old bridge like a pier foundation at the north end right next to the current structure. Since this photo was taken in 1940, the bridge had up until this point taken about two years to complete and the foundations with the concrete piers were contracted out, while the Railways Department itself built the spans and moved them into position.

The original bridge at this site appears to date from 1899 in fact even though there was an earlier railway bridge there. There was no road bridge in that area before that time because an earlier bridge existed at Onepuhi, some 5 km upstream. But the Rangitikei River is subject to severe flooding and at various times there has been a lot of damage caused to bridges crossing it, and in fact in 1882 the railway bridge of that era was washed out to the extent of three spans. In 1897 the floods of that year washed out road bridges at Bulls, Vinegar Hill and Onepuhi, and the Kakariki rail bridge was significantly damaged as well. It appears a new bridge which would also carry traffic was constructed after that event and was finished in 1899. However not all of the local residents were enamoured of the new arrangement and as early as 1912 there was agitation for the railway structure, which must have been heavily used with the completion of the NIMT, to again be separated from the purpose of carrying road traffic. Of course this did not in fact happen until March 1941 with the actual completion of the current railway bridge.

The woolscour plant at Kakariki which was shown on the map in the previous post also has a varied history, being originally built in the 19th century as a flax mill, then in 1917 changed to a freezing works which operated for only two years. During World War II it was used for cool storage having been converted with plant obtained from salvage of a ship wrecked at the Wanganui Heads. In 1948 it became a wool scour plant and at the time of its closure in 2006 was owned by Feltex, which went into receivership and was bought out by Godfrey Hirst.