Saturday, 14 August 2010

Ballast Pits on the Waiau Branch

In the course of putting together recent articles concerning the Waiau Branch and in drawing up the maps previously for the NZ Rail Maps site I have become aware of the locations of various ballast pits in the area, most notably because of Google Earth coverage as well as Google Maps and NZTM maps showing property boundaries. This knowledge has also been checked against information contained in “The Great Northern” which is the published history reference of the branch line. It would appear that all known or possible locations identified to date were between Hawarden and Waiau.

In TGN some of the ballast pit locations are described as being a certain mileage in reference to the known location of stations. To clarify this, the table below shows the information which was published in the book having been obtained from various Working Timetables. This is compared with the Curve and Gradient diagrams shown on the NZ Rail Maps site which were published in the mid 1960s.

Station Name TGN C & G Diagram
Amberley 33 m 40 ch (33.5 m)  
Waipara 40 m 36 ch (40.5 m)  
Waikari 49 m 43 ch (49.5 m)
9 m 7 ch (9.1 m)

9.0 m
Hawarden 53 m 20 ch (53.25 m)
12 m 63 ch (12.75 m)

12.75 m
Medbury 57 m 3 ch (57.0 m)
16 m 47 ch (16.5 m)

16.5 m
Balmoral 61 m 78 ch (62 m)
21 m 43 ch (21.5 m)

21.4 m
Pahau 65 m 69 ch (65.85 m)
25 m 33 ch (25.4 m)

25.3 m
Culverden 68 m 75 ch (69 m)
28 m 40 ch (28.5 m)

28.4 m
Achray 74 m 14 ch (74.2 m)
33 m 59 ch (33.75 m)

33.6 m
Rotherham 76 m 2 ch (76 m)
35 m 47 ch (35.5 m)

35.5 m
Waiau 81 m 61 ch (81.75 m)
41 m 25 ch (41.3 m)

41.2 m

It would appear that the distances from Christchurch have not changed greatly but I have not attempted to check if they have since the remeasurement of the line in more recent years. There are probably some changes in distance resulting from the three significant deviations in the line between Christchurch and Waipara (Kainga, Ashley and Balcairn) but I do not believe these would be significant.

The main issue found with the locations at TGN is simply that there appear to have been two other locations in the Medbury area that could have been used as ballast pits, or if not, other kinds of pits, if we assume that their location directly alongside the railway track was not coincidental. Google Earth helps us to find these locations these days.

Let us now consider the possible locations as they occur going along the line. First up we have the statement on TGN page 185 relating to two known pits in the Medbury area. Firstly that at “55 miles 22 chains 77 links, some 1 miles 60 chains south of the station”. This location is shown in the map below.

View Larger Map

As there is not much in the way of visual clues, all we have to go on as of now is the map view which shows us there was a widening of the property boundaries in this area. This might have allowed for a siding or loop directly alongside the track at this point although the book states that two sidings existed.

Going further north we have the location shown directly adjacent to Gilberts Road crossing, about a mile further on. If it had not been for the actual mileage being given for the first pit I would have suspected a measurement error. I have seen this area and it is clearly lower than the surrounding land in a way that suggests excavation. The regular boundary along the eastern side tends to suggest this is a man made division that would have supported a siding spreading out from south facing points at the south end.

View Larger Map

As we continue north we find this location just on the north end of the Waitohi River bridge.

View Larger Map

What you can see on the left of the railway embankment is old river terrace. The location to the right which is suggested as a possible ballast pit is on a separate land title. Again the triangular shape suggests that a siding could have run along this boundary with the north facing points at the north end.

Carrying on into the Medbury station yard we have the well known pit quite visible, this was used for road gravel or similar in the 1980s when I first went to Medbury. After the Weka Pass Railway lifted the tracks in the yard, the pit was extended through the former station site. However this site is now closed.

View Larger Map

However the description suggests the siding points were half a mile further on which is a considerable distance. It does seem unlikely to me that there were two pits very close together, but obviously it could be possible.

Moving north we have the knowlege of the “Balmoral ballast pit”. The first possible candidate is shown below:

View Larger Map

In the main, this location is to support the description given in TGN p.190 but no corroboration has yet been found.

The second location is shown below:

View Larger Map

Evidence to  support this location is found on the curve and gradient diagrams which show a “ballast siding” 1 mile south of Pahau, and on maps which show that the rectangular land area is on a separate title. The large rectangular area obviously is able to be visually identified as matching the description of a pit as well.

The next location that can be determined with any certainty is just at the north end of Culverden yard and is shown on diagrams of the area and as below.

View Larger Map

The pit at this location is shown on TGN page 194 and briefly referenced there and on TGN page 41 but without substantive description other than that it closed in 1959. I presume that other locations such as Glasnevin south of Waipara, must have been used to supply further ballast needs since it appears all the ballast pits on the Waiau Branch were closed by 1959. There is a specific Railways file found by searching Archway that references the adjacent Culverden school (which can be seen next to the pit site) as well.

Continuing north from Culverden we have this undocumented location about 2 km south of Achray:

View Larger Map

The depressed area is on a separate title from the rest of the area. It is of course hypothetical without corroboration.

Finally there is the reference in TGN p214 to a ballast pit at Waiau. The most likely location for this seems to be the gravel pit clearly visible on aerials, as seen below.

View Larger Map

The general area is currently a rubbish transfer station, and prior to that may have been an actual landfill for the area. The process of local government reorganisation starting in 1989 resulted in most municipal landfills in Canterbury closing and if there was one here it likely closed in the 1990s.