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How to use the OS Map Page

Signal Fact 37

Colour light signals were introduced for the first time in 1904 with the opening of the Great Northern & City Railway.

Although automated, they were lit by oil and had 'moving spectacles'.

When you visit the OS Map page you will probably find it takes a while to open up. This is quite normal because there is a substantial amount of data to download before it can be made visible. Please be patient! If you are on a metered or capped data contract it may be better to wait until you are able to connect using an unrestricted broadband connection.

A considerable number of the markers viewable on the previous OS Map page have yet to be converted for showing. Work continues on the conversions and the markers will gradually appear alongside new markers as the system expands.

This page is a work in progress and the Webmaster will always appreciate information for inclusion in the listings.

About Ordnance Survey Maps

These are invaluable for research and a page showing current Ordnance Survey maps is available on this web site. The map is capable of showing 'markers' and these are being added steadily to assist pinpointing the location of places included in the RailRef Line Code listings. The scale of the maps used when calculating grid references means that 'markers' may be slightly off their true position or overlap. This will be sorted out as time permits. To separate overlapping markers use the scale settings or your mouse wheel to zoom in.

For explanations of the maps themselves and the symbols used on them you will need to visit the Ordnance Survey's own web site. The explanations that follow tell you about the layers we have added on top of the maps.

Top Left - the plus (+) and minus (-) symbols

These symbols can be clicked on to zoom in (+ plus sign) or zoom out (- sign). You can also zoom in and out using the centre wheel of your mouse if you have one or, on touch screens, by the usual finger gestures.

Below these symbols is ....

The magnifying glass (🔍) symbol

This is a gateway to a large database of present day place names, addresses and post codes available via the Ordnance Survey's computers. Click on the symbol to open the search box and simply type in what you are looking for. As you type, a drop down box will appear with a list of choices which you can scroll down to select. The more precise you are with your question, the more relevant will be the list of choices.

When you click on one of the choices the map will automatically move and centre on the location you have chosen. Be aware that the information in your browser address bar does not change so refreshing the page will take you back from whence you came.

You can use this facility to move the map to locations not yet included in our own Gazetteer (below).

Continuing down the left hand side we come to ....

The Gazetteer

.... which is a list of all the features (markers) that we have added to the layers above the maps. The number of these is increasing as we bring forward all the ones that were on the previous map page and add them. Markers that have yet to have their position verified will not be added to this list until that has been carried out. Wherever possible features such as signal boxes are listed under all the names they have enjoyed during their lifetime. Features such as tunnels and public road crossings are listed by name.

Selecting one of the entries in the gazetteer will reload this page centred on the feature or place you selected.

In the list of place enames you will usually find the RailRef Line Number associated with the location. This should enable you to select the place of interest to you even though some place names appear in more than one part of the country.

Researchers should note that other marker details have generally been taken from OS maps, past and present, station dates from Quick's "Railway Passenger Stations of Great Britain", and line dates from Colonel Cobb's Atlas. Researchers are advised to check back to primary information sources before using the information! And advise the webmaster of any errors spotted.

Top Right - The Mouse Position

When you move your mouse into the map window a window opens which shows the current co-ordinates of the mouse position in three different forms. As you move around the map this information constantly updates.

Below that is a stack of 'tick' boxes .... the layer switches.

Layer Switches

The information we add is stacked in layers that can be indivually hidden from view or revealed. Most are switched on when you enter or refresh the page but can be hidden by removing the tick and revealed again by ticking the box again.


Below the switches is a button labelled Legend. Click on this to go to a page where the usage of the map page is explained in detail - in fact, you are reading this page now!

The Layers Explained

The OS Map page makes use of the OpenLayers open source system which has become an internationally recognised standard for display of mapping on web pages. The page makes extensive use of the Javascript programming language which is recogised by modern web browsers.

Both the maps and the line and marker information we have added are segregated into layers. Layering in this way allows you to make each layer visible or hidden from view as you wish. The maps form the bottom layer and the other information layers sit above them.

When you hover your mouse over the lines and icons a brief statement will appear. To see more information where it is available click on the line or icon.

If you go in search of any of the features and markers shown, please ensure that you do not trespass on private land or on the operational railway.

Lines & Yards

This later contains lines of route both present day and those that no longer exist that have been added to our mapping database. The lines are colour coded in order to distinguish between different companies lines based on the RailRef Company Code. The colours repeat on the map as a whole - there are more railway companies than easily distinguishable colours!

Hovering over the line reveals up to three pieces of information:

  1. The line number identity in the RailRef numbering system (e.g. AA001). The two letters denote the company that used to operate the line or who would have if the line had been built when that company existed. The three digits are a sequential number with a separate series for each company.
  2. The Engineers' Line Reference allocated from the system originally developed by British Rail in the 1980s and still used today by Network Rail assuming it has one. Lines closed many years ago or transferred to other operational bodies are only included where BR had continued to be responsible for surviving infrastructure.
  3. The year in which the line opened and, where appropriate, closed.
  4. On sections of line in tunnel the tunnel name will appear instead of the date(s).

Clicking on the line will open a pop-up box with more information including the name of the company that built it.

Solid lines are used where the line is still open for traffic and broken lines where the line is closed. Tunnels are distinguished by varities of dashes and dots as are underground, metro and tramways.

Yards and extensive sidings are shown as coloured areas.

Please be aware that lines drawn at one scale may not appear as accurate when viewed at a different scale. This is caused by how the Ordnance Survey represent things the maps at various scales combined with the pixel grid on the display you are using.

Signal Boxes

Included here, denoted by , are all forms of signal box from mechanical right through to Regional Operations Centres. Within this layer are ground frames, shunting boxes and control rooms and newer railway junctions that are remotely controlled.

The icons used in this layer are:

Hovering over the icon reveals up to three pieces of information:

  1. Name. There may be more than one if it was renamed at some stage.
  2. Identity in the RailRef numbering system (e.g. AA001-010) consisting of the line number a hyphen and the sequential number of the signal box along that line. If this is missing then the location does not (yet) have a RailRef identity.
  3. A date or date range where successive signal boxes of that name or identity were located in different places.

Where the signal box is listed in one of our published Signal Box Registers, clicking on the icon will display an updated copy of the signal box register entry if one is available. There may be other information or links displayed in the pop-up box as well.

Where signal box details include a message that the position of the box on the map is “rough”, this indicates that 8 figure co-ordinates from the svrsig system have not yet been checked to enable them to be converted fully to 12 figure co-ordinates for this page. The position shown will be up to 200 metres out. The number of boxes affected by this will be reduced with the passage of time.

Signal boxes of the Lancashire & Yorkshire Railway, North Eastern Railway, and the northern parts of the London & North Western Railway are generally omitted at present but will be added when the process of allocating RailRef identities is completed. Other signal boxes for which no co-ordinate information is available are similarly omitted until their position can be verified.

Level Crossings

All kinds of level crossing are shown including many that have been removed with the passage of time. Inclusion of a level crossing marker is not evidence of any public right of way at the location indicated unless it is a crossing of a public highway. Do not trespass on the railway!

Use has been made of a Network Rail level crossing list dated 2013 which had been obtained under Freedom of Information provisions. Where a line remains in Network Rail ownership and the crossing is marked as not being on this list, is is very likely that the crossing had already been closed by this date.

The icons used on the crossing layer:

The name or number of the crossing by which it known to the railway is given where it is available. The origin of some of these names has been lost with the passage of time and they may now be known by a different name locally or even to the Ordnance Survey.


Passenger Stations are indicated by use of the “double arrow” symbol originally designed by British Rail and now used generally by Ordnance Survey and others for this purpose even where the station has never been part of the national railway network. The symbol is the copyright © of the UK Government.

The symbols used on our map layers are colour coded:

Railway stations are usually lengthy and we may have chosen a different point within the station to the one used by Ordnance Survey for their marker.

Some other railway and industrial premises are included in this layer and indicated by


Bridges are always considered from the perpective of a train passing along the railway line. Two key sources have been used: lists of bridges and tunnels obtained from Network Rail under freedom of information arrangements and a similar list of structure that were in the care of BR Residuary.

Railway bridges shown in this layer fall into one of four categories with each category distinguished by a different icon:

Side bridges are generally omitted as they are difficult to adequately locate or pinpoint on the map without making a site visit.

The name or number of the bridge by which it known to the railway is given where it is available. The origin of some of these names has been lost with the passage of time and present day users are sometimes surprised or baffled by the name shown on the modern bridge identification plate.

OS Map

The maps are those currently available as Open Data from Ordnance Survey (OS). OS is reponsible for the content of the maps and what is displayed on them. Two different maps included and the appropriate one is selected automatically as you zoom in or out.

You can scroll the map layer north, east, south and west, and up and down and sideways as well. Left Click with your mouse and hold the click down to drag the map layer and the dynamic layers will follow as well. On touch screens just use your finger as the mouse!


Apart from location markers there are a few links to the Ordnance Survey maps held by the National Library of Scotland (NLS). These links are only shown at a small number of places but the facilities they lead to allow easy navigation to alternative locations. The NLS has coverage of England, Scotland and Wales but some map types are only held by them for Scotland. Their site allows the map to be made transparent so that a modern view can be seen as well (but without the overlays) and the maps can be viewed in a larger window without any artificial overlay added.

To fully explore what the NLS has to offer you need to visit their web site. Two links are provided from the map page marker. One takes you to the main map entry page and the other brings up the 25 inch map from the 1890-1910 period for the location.

These links can be identified by this icon on the map.


The boundaries of county, unitary and other local authorities can be seen by making this layer visible - it is hidden by default. These boundaries are those currently recorded in the OS system. Zoom out to see them to best effect.

Copyright Issues:

Ordnance Survey mapping is licensed under the general terms and conditions allowed by the UK Government's Open Data License. Parts of the OS Map page source code was provided by Ordnance Survey. Other parts are from the OpenLayers open source system.

You are welcome to reproduce the information on the OS Map page provided these conditions are observed:

  1. If you include any of the information we have added in any of the layers we have added you must include an attribution that the information is the copyright of the Signalling Record Society and provide a link to our web site.
  2. If you include the background map or the boundary layer you must include an attribution that the information is Crown Copyright and Database Rights plus the calendar year in which you made the copy of the screen image.
In either case you may share the information but you may not make any charge for its use and you must require that any recipient of the information also complies with these conditions.


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Page last modified Thursday, 19th May, 2022, 16:52 hours.
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