Sunday, 19 November 2017

Otago Central Railway [50]: Finishing Otago Central and other maps

As I get to the completion of the maps (or as complete as they can be made) I have to look at how practical that is to achieve and how long it will take etc. So far as the Central goes I have only had access to chainages for 25 miles to 146 miles (about Pukerangi to Cromwell). From other resources available to me, I can still mark in and have been adding milepegs for 0-25 miles for consistency with the rest of the maps and it has been possible to number most of the bridges correctly for that section as well. Whilst there is another chainage book for 0 to 25 miles which I could get a copy of I have decided not to enquire further about this as I am not willing to spend any more money on researching this line, it's cost a lot already and I don't feel there is any real benefit to be achieved at this time.

The initial section of the line which is currently open as the Taieri Gorge Railway also doesn't have much in the way of aerial photography available at this time so it's not possible to fill in all the missing details in the way that has been possible to achieve with the other parts of the line. It may well be the case that over the succeeding two years more high quality aerial photography will become available from the Retrolens website but right now there isn't a lot there. Some details can be filled in from Linz coverage in places.

I am quite certain this part of the project is winding down and will be spitting out the Cromwell maps in the next day or two, then what I need to do to complete my series of articles will be a key priority, and it's assured that the work on the overall project will slow down after that - not stop completely, but it's unlikely to be a daily activity to the extent it has been in the last few years. Also the focus for the other maps will be mainly finishing them as they are now - if there is detail in Linz's photos that is easy to copy it will be copied, but I won't be spending time on historical stuff to the extent I have on the Central.

One of the things that is important to me on all the maps is not to use metricated imperial distances. As previously outlined the measurement namespaces for the two distinct series of measurements, the imperial and metric measurements of most lines, are generally different and not directly convertible, and one of the issues in the rail community has been the use of converted imperial measurements without realising the actual numbers may not be directly equivalent. There are a few places where I am relying on a metric measurement from Over the Garden Wall without being able to tell if it is really a distance that was measured in 1974, or one that has been converted from a previous imperial number, and to the greatest extent possible I have used the imperial measurements wherever I can for places that didn't exist at the time of metrication.