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'''Glossary of Railway Terminology as used in this wiki'''

It is important that users get to understand the exact meaning of what are sometimes very common terms that can be misunderstood. This glossary is something that will be added to as time goes by and like all pages in this wiki, can be printed out for those that might prefer to have a hard copy close at hand.

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== '''RAILWAY''' ==
The technical definition of a Railway includes steel wheels running on steel rails with a track gauge greater than 610mm . To operate a railway you must comply with the Railway Act, which defines all matters relating to the safe operation of the railway 

== '''TRAMWAY''' ==
A Tramway is generally defined as a railway with a track gauge of 610mm or less. The operation of a Tramway does not need to meet the strict safety requirements that a Railway does.

== '''STATION''' ==
This very common term has multiple meanings and we need to clarify them. 

1. In this wiki, the term is used in the general sense of a location where railway activities occur. The Railway system is made up of  railway lines and along those railway lines there are stations where things happen. These could be as minor as just scheduled stops for a passenger train, or include full freight, marshaling and servicing facilities. Another way of viewing a station is recognising it any place that has (or had) an official railway name. All station have a name with an official spelling. In general there are no two stations with the same name, although there are instances of a name being re-used at a different location after a station elsewhere has closed. Where there were two stations with the same name, one of them receive North or South as an addition (e.g. Palmerston and Palmerston North), sometimes with strong opposition. 

A very large part of this wiki is be based around stations and the structured breakdown of larger yards into smaller, logical chunks. 

2. The term station is often used to refer to the building at a railway location. In this wiki we will always refer to it as the 'station building' rather than just the station, unless it is unmistakable that in the context we are referring to just the building.

3. The term Station can also be used when referring to a large (generally sheep) farm, mainly in the more isolated parts of the country where the railway sometimes passes through. Should reference need to be made to these, they will be referred to a sheep, cattle or high-country station.

== '''MAINLINE''' ==
The railway network is made up of railway lines between stations, with every Line having an official name. The major lines are called Mainlines and in New Zealand there are only four: the North Island Main Trunk (abbreviated NIMT) and the East Coast Main Trunk (ECMT) in the North Island and the Main South Line (MSL) and the Main North Line (MNL) in the South Island. All other Lines are Branch Lines

Even Main Lines have a heirarchy, in that where one Mainline starts at an intermediate station of another Mainline, it is then the secondary mainline. So for the North Island, the NIMT is the primary Mainline and the ECMT the secondary as it starts at an intermediate station of the NIMT, in this case Frankton. For the South Island, the MSL is the primary and the MNL is the secondary as it branches off the MSL at Addington.

== '''BRANCH LINE''' ==
As the name implies, a Branch line branches off a Mainline. There is an exception though where a Line is not connected to any other line and the prime New Zealand Example is the Nelson Railway.There being only one track, it was usually just referred to as the Nelson Section. 

While there is no formal distinction, there are a number of Branch lines that do not have the word Branch in their name, just Line, and these tend to be branch lines to which a greater regional significance is attached. They are: The Midland Line (originally envisaged to go from Rolleston to Nelson), the Stillwater - Westport Line (now the Stillwater - Ngakawau Line), the Wairarapa Line, the Palmerston North - Gisborne Line, the Marton - New Plymouth Line and the North Auckland Line

== '''TRACK SECTION''' ==
The portion of track between stations is known as a track section and for convenience, this wiki has been divided into sections based on all the stations that ever existed, and the track sections between them. Most stations have disappeared long ago, some with tell-tale signs still around, others without a hint that a railway ever existed there, Eventually I envisage a map will be available for each Station and section to help understand where closed railway lines ran.

== '''ALIGNMENT''' ==
This is the term used to describe the shape of the track. The ideal railway runs in a straight and level line from start to end, but we all know that is not feasible because we have hills to negotiate, sometimes by climbing up and over them, other times by going round them. It is the engineers task to find the most economical route. Most of New Zealand's railway lines were built 100 or more years ago, at a time when labour was cheap but equipment was virtually non existent. The alignment that the engineers worked out was then usually the one that required the moving of the least amount of earth and rock. Sometimes a tunnel was the only solution but it was certainly not a preferred solution. Bridges too were expensive and avoided if possible, but New Zealand has lots of Rivers and the decisions on where to cross major rivers often has a significant bearing on the final route the railway took. South Canterbury is a good example where extensive discussions took place before a suitable crossing point for major rivers like the Rakaia Rangitata and Waitaki (among others) were agreed to. 

Railways that have been designed and constructed in more recent times usually aimed for a balance between construction cost and operating cost. Alignments that have lots of steep hills and sharp curves are more expensive to operate than ones with flatter curves and grades. The machinery we have available now make it much easier to remove part of a hill than have to construct a tunnel for instance, and very high concrete bridges can now be built with very large spans, avoiding massive embankments or a much longer journey.

== '''LINEAR REFERENCING''' ==
This is a technical term used to describe a method of being able to locate something along a Railway Line. Prior to 1974, all distances were referred to in Miles, Chains and Links, with 100 Links to a Chain and 80 Chains to a Mile. Distances along the railway were then referred to as the Mileage. Along the railway line you had Mile posts  plus ¼, ½ and ¾ mile posts. From these you could fairly easily measure to any point along the line. 

These Mile posts were however technically known as a Reference Post, in that once they were installed they were not moved. There were however many instances where the track position changed due to engineers deciding on a better alignment maybe to make the grade less steep or the curve not so sharp or to avoid  a piece of unstable ground. Each of these situations could either lengthen or shorten the track but would not affect the position of the Mile posts either side of the work. This resulted in what was termed Long or Short Miles, and over the years when quite a number of these situations had occurred, the true length of the track was not the same as the originally measured length anymore.

All old records still have the Mileage figures associated with them. To understand where something was along a railway line, and all you have is the Mileage, you need to be able to relate it to something that still exists and you can find the mileage for, and then work out the difference in mileage, convert that to metres (or kilometres) which you can then use to find the position you want. In order to overcome some of those problems, We intend to provide the Mileage of all the old stations (and many other points) to enable inbetween points to be located with a fair degree of accuracy 

In 1974, New Zealand took the big step of changing the measuring system we used from Imperial (British) units to Metric (or SI) units. NZ Railways at the time took the opportunity to remeasure all of its remaining operational lines (some 4000km) and produce new records of all the  items along the track. This task took may people many months with the track first being marked out in 30m intervals measured with a steel band, from which the full and half km positions defined, then using those as references, the position of all the items in between were recorded, This final measuring was done using a measuring wheel, reset to 0 at each km post. Even with the greatest care, mistakes were made and a number of km distances ended up 30m or more over or under. However, the new km post positions remained where they were first measured.