Network Rail Node IDs
Abstract
An explanation of how Node IDs are used in the WRc Network Rail reporting environment
Contents
Introduction
WinCan VX contains an inspection template for Network Rail that is based upon this document, published by Mott MacDonald in 2013:
Note that this document is old and it refers to the WRc MSCC4 and has not knowingly been updated since. Until we are informed that it has been updated for MSCC5, WinCan has no requirement to create a MSCC5 variant of it and no customer has requested it.
The specification of the data formats inside are similar to DMS since the document comes from the same authors, but it is far less complex.
Further information is contained in here, published in 2018:
We do not have any other documentation on the requirements for Network Rail CCTV surveys other than what is published here, and it is the contractor’s responsibility to follow and understand these requirements before undertaking work on the rail network.
It should be noted, that the specifications defined in these documents are absolutely for trackside data collection. They are all about naming assets by locations along the railway line, so are not applicable to inspection projects that are not trackside, like for example the TV inspection of some problem customer toilet drains or car park drains at a railway station.
Just because the land owner is Network Rail, does not imply that this standard should be used.
Node IDs
The most common question we get regarding this inspection standard is why is the node ID field limited to 7 characters, where in regular WRc standard, it is 10 characters. Customer have often requested that it be extended because it is not fit for purpose.
It is 7 characters because that is what the attached documentation requires, but there are other fields that need to be used alongside the node ID to create the full node reference in line with this specification.
See in the first attached document on pages 24-29 there are a number of tables where the data contains columns with ‘Ellipse Asset Number’ and/or ELR:
Ellipse Asset Number is the actual ID of the node, this is the 7 digit reference field, and see in the example tables given that they are always 7 characters.
ELR is the Ellipse Line Reference which is data that should be given to you by the employing authority that refers to the line that you are working on, 4 characters.
See on pages 34 and 35, the length definition for these fields:
See in the WinCan VX section header that we have fields for these values:
These are node points, manholes, catchpits, whatever you want them to be at the upper and lower ends of a pipe in most cases, but to truly record the precise details of each node, you must also work in the nodes area of WinCan VX, see here:
See here that there are a number of mandatory fields, but in particular take note of the Node ID (the 7 character Ellipse ID), the ELR (the 4 character Ellipse Line Reference) and the Mileage (numeric).
The Mileage is defined as a distance in miles and yards from the start of the line, usually in London if the line goes to London. You might also see other references like ‘Up’ and ‘Down’ in some fields and these are similar to the side of the road that you are driving on, and refer to ‘Down’ to London and ‘Up’ from London, so the direction of the track.
It is all of these fields that collectively make the true node ID, not just the 7 character single field, and all these fields should be used in harmony to create an accurate reference in line with this standard.
Here is a worked example of 2 nodes and a pipe correctly created using this system:
Notice the 2 different node IDs, both within 7 characters, the same ELR and Delivery Unit, but see the difference in the Mileages
CP200 is 6701 - 6671 = 30 yards further up the line from London in the 10 ft cess space from the centre line of the track.
Of course, it’s not possible to have 6700 yards in a mile, but this is just a model exercise to illustrate how it works.
1 mile = 1760 yards
1 mile = 80 chains
1 chain = 66 feet (22 yards)
Chains were commonly used in Victorian times for accurately measuring distances along the line, because they do not change length with hot and cold temperatures, and can be dragged along the ground and laid in a tight line. They really were chains, it is not just an odd word for a unit of length. Sometimes you will see this as a distance like 68ch.
It is also why you see references to ‘chainage’ in DMS data files for distances. It is just an elaborate way of saying the same thing where the author of both specifications is the same.
Of course, WinCan VX also allows you to accurately plot the nodes with coordinates using GPS, which it could be argued make these mileage values obsolete, but this is just what the documentation specified, and until it is updated, we cannot change it.
So, now I can create a pipe between these 2 nodes in the Section Header:
See that now, when you specify a node, the other corresponding data that you collected in the Node form is brought in also.
See in the pipe report, we have all the information that is required:
And also in the node report:
Going back to the original document and pages 24-29, you will see asset references like ‘BTH3_CCTV01’ quoted as a reference:
All that is happening here is that the client is combining the ELR (BTH3 in this example) with the node ID to create a reference of their own, so there are actually 11 characters being used here, but it is the client’s choice to name assets this way if they want to, which is why the different elements of the reference must be stored in different fields in the WinCan VX database, and subsequently exported into the XML file as separate tags.
Cess Space
You will have seen in this data references to the ‘Location’ as being terms like '6ft - Up' and so on.
This is a location or distance relative to the centre line of the track and also defines which direction the line is running, so the smaller the number, the close it is to the track centre line.
It is often referred to loosely as the cess space, because trains often spew their toilet waste alongside the track at high speed. By doing this, the waste gets sprayed and spread so thinly across the ground and surrounding vegetation that it is barely detectable and causes no significant risk to public health because there shouldn’t be anybody on the side of the track anyway.
On the very rare occasions that there are workmen on the side of the track when a train passes, they always stand with their heads bowed and their backs to the train, because they never know if someone is going to flush a toilet on the train just as it is going by.