See Also: Features  •  Length Conversion Tables  •  Definitions


Usage

The railway or geographic information contained within this web site should not be deemed as definitive, complete, or entirely accurate. Consequently, the information must not be used in any manner which could adversely affect the safety of railway personnel, passengers, members of the public, or negatively impact the environment. The contents of this web site should not be relied upon for any production or safety-critical tasks within the railway domain.

Background

The information provided on this web site is intended to give an indication of notional mileage / kilometreage positions on Network Rail owned or maintained railway lines, as defined by an Engineer’s Line Reference, commonly referred to by the acronym ELR.

Scope

All Network Rail owned or maintained lines are included, irrespective of their current operating status.

Accuracy

It should be noted that the tabular data and associated map markers may not necessarily reflect the accurate geographic position for the specified mileages in all instances.

Inaccuracies can result as a consequence of individual or combined events, such as railway configuration alterations, data accuracy anomalies, or external factors. For example, a route may have been realigned or rationalised, consequently altering the linear distance between the original mileposts. The original milepost may have been removed and repositioned in an incorrect position during engineering works, or the milepost positioned at the end of a structure to avoid placing a conventionally-constructed milepost in an unsuitable position.

Computing the definitive geographic position of a mileage on an ELR therefore needs to consider that the reported length between the entire line and between mileposts on the line will not be an exact match for the geographic linear distance. As such, the indicative geographic position of a railway location (i.e. ELR and corresponding mileage) is computed with a corresponding linear accuracy measured along the railway. This accuracy (for example, ±6 metres) is based on the measured linear distance between the adjoining mileposts for a given mileage.

Consideration of data validity and corresponding linear accuracy is incorporated into each of the computation build stages, transforming the originating raw datasets into usable information contained within this web site. The key outputs of this validation are presented in various ways within this web site as noted below:

  • Summary: The reported length (i.e. between the start and finish mileage values) of an ELR is compared against the computed geographic length (referred to as the measured length). Where there is a noticeable discrepancy between these two lengths (based on automated and manually-reviewed analysis), this is recorded on the ELR summary page as either a Caution, Warning, or Extreme Warning, depending on estimated severity. Where there are recorded anomalies with the ELR’s accuracy, these are noted within the Remarks section.

  • Positional Accuracy Statistics: Statistical analysis of the accuracy between each milepost in an ELR is computed. This is represented in summary form to give an indication of estimated linear accuracy for each ELR.

  • Mapping: The estimated linear accuracy is depicted on the interactive maps by the marker colouring. Dark blue marker colouring indicates a good linear accuracy of ±4 metres or less. Map markers with a lesser linear accuracy are shown in a light blue colour, and the accuracy value can be viewed by clicking on the marker.

  • Correlation: An automated test suite runs a validation process for the GeoFurlong-computed geographic positions against multiple datasets known to be produced by Network Rail. At present, this combined dataset contains over 300,000 items of infrastructure with ELR, mileage, and geographic position. The output of this validation process indicates excellent correlation with Network Rail-computed geographic positions.

In addition to the automated validation steps noted above, considerable effort has been expended on the manual review of the computed geographic positions of mileages on ELRs. These reviews have been undertaken using a combination of satellite imagery, historic records, and site-specific knowledge against a wide range of known and identifiable infrastructure features.

Attributions

Licence

All outputs contained within the web site are released under a permissive CC BY Creative Commons Licence. This licence allows reusers to distribute, remix, adapt, and build upon the material in any medium or format, so long as attribution is given to the creator. A suggested attribution for reuse is: Data provided by geofurlong.com. The licence allows for commercial use. To facilitate reuse, the tabular information presented on the web site pages has been specifically designed to allow easy transfer to spreadsheet-type applications via standard copy and paste operations.

Privacy

The web site does not store cookies or any information which could identify or track its users. The back-end infrastructure suppliers serving the web pages and background map tiles record usage for billing purposes, however no personal information is recorded. No affiliate links are included when linking to external web sites.

Credits

The web site is built using the Hugo framework with the PaperMod theme, deployed on the Netlify platform using background map tiles provided by Lima Labs controlled by the Leaflet library.

Web Site Theme

The web pages can be toggled between light-on-dark and dark-on-light mode by clicking on the ‘sun’ or ‘moon’ images next to the main GeoFurlong text at the top of each page.

Disclaimer

THE CONTENTS OF THIS WEB SITE (geofurlong.com) ARE PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL THE AUTHORS, DEVELOPERS, CONTRIBUTORS, OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE WEB SITE CONTENT OR THE USE OR OTHER DEALINGS IN THE WEB SITE CONTENT.