NZRM Progress Report 2023-06-30: Midland Line, Volume Reorganisation

This week the main work done in the Project has been in the Midland Line. The mosaic of Greymouth in 1945 was completed and has been used in mapping. It is fair to say the planned release of Volume 9 is a bit behind schedule. For reasons explained below, the release of what has been completed to date will now be effected, which will be mostly the mainline section. This will be finalised and produced next week.

The second thing that has been going on this week is reorganising the volume structure for the maps. This is the fourth and, it is confidently expected, last volume reorganisation. It is useful to look at why the project is divided into volumes. For the webmaps and the image based maps it actually does not matter at all which volume they are in. The volume structure was originally conceived for the purpose of producing books or PDF files of a collection of maps together. Currently this format is not being maintained, but it certainly is still planned to output these physical volumes as part of map production in future.

Apart from physical volumes, the main reason a volume structure is implemented is for the following reasons:

  • For the reason of project organisation / structure. Instead of having all the maps in one big project, having them split into a number of projects is important for effectively managing the map data. It helps to create redundancy in the data which limits the impact that file corruption can have on the various datafiles.
  • For the reason of organising GPX files. Some GPS devices are limited to 1000 locational points that they can store in a file at one time. This means that the project’s GPX files will be structured to work with this limitation. So it is not possible to put all of the locational points in the entire project into one GPX file because that would be a much greater number than 1000 (there is currently about 4000 km of operating track in NZ right now, so that is well over 4000 points that would have to be stored).

This week’s changes have been along the lines of equalising the size of volumes. It turns out that NZ has had 6000 km of railways historically. Kiwirail has records of around 4000 kilometre posts although not all of it is open, but they will include mothballed lines. Taking the 6000 km and dividing it by 12 volumes gives 500 km per volume. So the volumes are being reorganised to each be 500 km approximately. This is better than the previous absurdity of volumes being different lengths from 110 to 990 km.

Because of this change, Volume 9 is no longer Volume 9. In the future, Volume 9 will cover Christchurch and parts to the south. The new volume for the Midland Line will be Volume 7 and it will include all of the railway lines on the West Coast in the same volume. The table below shows what is actually in each of the new volume definitions. Making each volume more or less consistent in size will have the advantage of making all the printed volumes more or less the same size so that their production and distribution costs are the same. It also means each GPX file will have plenty of room in it to store around 500 km pegs as well as all the stations within that area. Thirdly, it makes it easier to estimate how much time is needed to complete each volume consistently if they are all of a very similar size.

The Project realises this change will not suit everyone but there is in reality no actual perfect way of organising the map volumes that will serve every possible situation or purpose. What is relevant is that this structure will not affect the way image based maps or webmaps are produced. The webmaps will continue to be completely seamless i.e. a single map, whilst the image maps will still be output the way they are now organised by the name of the railway line that they cover. In fact the Project is considering changing the downloads pages into ones that are organised by line name rather than volume name. Because of the changes, the existing volume categories will all be removed, as they are now out of date in a lot of cases, and the post captions will be altered.

What’s relevant for the here and now is that Volume 7 will not be completed this year so there is now not going to be a full release of the volume that contains the Midland Line. For this reason and also because of the need to get the Midland Line maps produced as soon as possible, the part of Volume 7 that includes the main line from Rolleston to Greymouth will be finalised and released ASAP. The part that includes Midland Line branches will be finalised and released sometime later this year.

Volume Definitions as at 2023-07-01

Volume 1 – Total 500 kmNorth Auckland Line
Bay of Islands Vintage Railway
298 km
Okaihau Branch / Rangiahua Extension (estimate)60 km
Dargaville / Kaihu Branches80 km
Onerahi Branch6 km
Riverhead Branch5 km
Newmarket Branch3 km
Onehunga Branch3 km
North Island Main Trunk from 635 to 680 km45 km
Volume 2 – Total 500 kmNorth Island Main Trunk from 224 to 634.5 km410 km
East Coast Main Trunk from 0 to 7 km7 km
Mission Bush Branch17 km
Waiuku Branch8 km
Glen Afton Branch14 km
Wilton Collieries line11 km
Raetihi Branch14 km
Cambridge Branch19 km
Volume 3 – Total 518 kmEast Coast Main Trunk from 7 to 182 km176 km
Thames Branch75 km
Paeroa – Apata60 km
Kinleith Branch65 km
Rotorua Branch51 km
Murupara Branch58 km
Taneatua Branch26 km
Mount Maunganui Branch7 km
Volume 4 – Total 498 kmNorth Island Main Trunk from 148.5 to 223.5 km75 km
Marton New Plymouth Line212 km
Stratford Okahukura Line143 km
Waitara Branch7 km
Egmont Quarry branch (estimate)10 km
Opunake Branch36 km
Whanganui Branch5 km
Castlecliff Branch6 km
Taonui Branch4 km
Volume 5 – Total 493 kmPalmerston North Gisborne Line from 7 to 391 km385 km
Moutohora Branch78 km
Ngatapa Branch (estimate)22 km
Napier Port Branch5 km
Wairarapa Line from 168.5 to 171.5 km (Woodville)3 km
Volume 6 – Total 456 kmNorth Island Main Trunk from 0 to 148 km148 km
Palmerston North Gisborne Line from 0 to 6 km6 km
Wairarapa Line from 0 to 168 km168 km
Foxton Branch31 km
Palmerston North Central Section (estimate)10 km
Greytown Branch5 km
Rimutaka Incline Section40 km
Johnsonville Branch11 km
Johnsonville-Tawa Section6 km
Melling Branch3 km
Western Hutt Section19 km
Gracefield Branch4 km
Hutt Park Railway3 km
Te Aro Branch2 km
Volume 7 – Total 513 kmStillwater Westport Line136 km
Seddonville Branch48 km
Cape Foulwind Branch (estimate)10 km
Conns Creek Branch3 km
Midland Line from 3 to 212 km210 km
Hokitika/Ross Branch62 km
Rewanui Branch13 km
Rapahoe Branch4 km
Blackball/Roa Branch8 km
Whitecliffs Branch19 km
Volume 8 – Total 500 kmNelson Section110 km
Main North Line from 33.5 to 348 km315 km
Mendip Section (estimate)9 km
Waiau Branch66 km
Volume 9 – Total 515 kmMain North Line from 0 to 33 km33 km
Sockburn-Styx Corridor (estimate)8 km
Stewarts Gully Section4 km
Oxford Branch (estimate)55 km
Eyreton Branch33 km
Main South Line from 0 to 165 km165 km
Midland Line from 0 to 2 km2 km
Little River Branch37 km
Southbridge Branch41 km
Methven Branch36 km
Springburn Branch43 km
Fairlie Branch58 km
Volume 10 – Total 498 kmMain South Line from 165.5 to 432 km267 km
Waimate / Waihaorunga Branch13 km
Kurow / Hakataramea Branch60 km
Ngapara Branch24 km
Tokarahi Branch19 km
Moeraki Branch3 km
Shag Point lines (estimate)5 km
Dunback Branch14 km
Makareao Branch5 km
Port Chalmers Branch2 km
Fernhill Branch3 km
Walton Park Branch4 km
Taieri Branch4 km
Taieri Gorge Railway60 km
Outram Branch15 km
Volume 11 – Total 504 kmMain South Line from 433 to 601 km168 km
Roxburgh Branch95 km
Taratu Coal Railway (estimate)15 km
Catlins River Branch69 km
Tapanui Branch42 km
Waikaka Branch21 km
Glenham Branch15 km
Bluff Branch25 km
Seaward Bush Branch54 km
Volume 12 – Total 554 kmKingston Branch140 km
Hedgehope Branch21 km
Waimea Plains Railway59 km
Mossburn Branch17 km
Waikaia Branch22 km
Wairio Branch55 km
Ohai Railway Board line19 km
Tuatapere / Orawia Branch71 km
Otago Central Rail Trail / Cromwell Gorge Section172 km
GRAND TOTAL approximate(some sections not part of NZR)6000 km



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