Geospatial Features of the Dean Forest Railway

The Dean Forest Railway (DFR) is the last remnant of a tight network of lines that once covered the Forest of Dean. The DFR presently has a distance of 4.55 miles and snakes its way gently uphill from the near the Severn Estuary into the Forest itself. This indicates the original purpose of the DFR, namely to bring the resources - minerals, coal and stone - found in the Forest to the world outside. I enjoyed a pleasant day, riding up and down the line. The line might in the future be extended into the Forest and on to Cinderford to give a total distance of about 11 miles, at the same time enhancing greatly what is already a good tourist attraction.

The Dean Forest railway snakes its way for about 4½ miles between the close arboreal confines of the heart of the Forest itself and the wide open expanse of the landscape of the Severn Estuary.

Now prepare ye for some plots and graphs. Not too overwhelming, but hopefully quite interesting! You will see here:

• How far is Parkend from the Centre of London?
• Outline Map of the DFR
• Height Profiles of the DFR
• Some Facts and Figures
• Average Rising and Falling Gradients
• Timing & Speed
• Map File
• And Finally


• Please Read Me! Thankyou!

How far is Parkend from the Centre of London?

Parkend Station is within a stone's throw of the The Fountain Inn in Parkend, our starting point for most of our walks on the previous days. The Inn itself is about 170 Km, or 106 miles, west of the centre of London. These figures are based on a bit of Spherical Geometry, taking the centre of London as the intersection of The Strand, Whitehall and Cockspur Street. This intersection is often referred to as Charing Cross, not to be confused with the Victorian Eleanor Cross itself nor the station in front of which it stands. The detailed figures, for the fun of it, are as shown below.

The Fountain Inn, which is close to Parkend Station,
lies about 106 miles west of the centre of London.

Outline Map of the DFR

The DFR strikes very roughly north into the Forest from the open expanses that characterise the Severn Estuary. The southern-most station is Lydney Junction with a connection to National Rail (NR). There are at present five stations, with Norchard the main operational centre.

The map grid scales translate to 1.112 Km per 0.01° latitude and a mean of 0.688 Km per 0.01° longitude (WGS standard), both when using 6371.0 Km as the volumetric mean radius of the earth.

Outline Map of the Dean Forest Railway

I plotted the map by hand on my return home. Because we don't live on a flat earth - unless you are a convinced "flat-earther" - maps are inevitably a distortion of what is. In other words, it's all a matter of mapping a curvaceous surface onto a flat surface. In our case, the northern length of our map grid is stretched out by an extra 0.16 %, to make it the same on the page as the length of the southern part of our map grid. The miniscule loss in accuracy is not really noticeable!!

Height Profiles of the DFR

The railway climbs gradually into the Forest, with Parkend - its present terminus - close to the highest point. Railway builders must chose their route carefully to avoid the more severe gradients acceptable for normal roads.

Height Profile

The above plot uses a true origin for the vertical elevation (height) axis, so as not to lose track of reality. What a worthy aim!

Some Facts and Figures

Here are some "vital statistics" in metric and imperial units. The total length of the line is measured on the surface of the WSG84 spheroid. However, we can consider this, without undue loss of accuracy, as being on a conceptual "flat" plane at mean sea level, using the OS sea level reference as explained on OS maps. There you are!

"Walk facts and figures"

For simplicity, let's put aside the fact that the actual distance travelled by passengers is about 4.20 miles as against the railway's present total length of 4.55 miles. The height difference between the ends of the line is 42 metres, but the actual climb (total ascent) required is more than this at 87 metres. It's the total ascent which is of course relevant when looking at the effort expended by the locomotive in bringing itself and its train up the line and into the Forest.

Average Rising and Falling Gradients

And here, for the numerical fun of it, are the average gradients for the DFR. The rising and falling (negative) gradients are both averaged over the distances given, with level stretches having rises and falls of less than ± ½ metre. The aggregate length of the level stretches predominates, which is not surprising for a railway. However, it is interesting to compare the gradients with those considered in connection with our Dean Forest WALKS.

Rising and Falling Gradients

Timing and Speed

Although the DFR is 4.55 miles (7.32 Km) long, the distance actually travelled by passengers is marginally less at 4.2 miles (6.8 Km). The standard timetable for 2016 gives times, in either direction, between Lydney Junction to Norchard and between Norchard to Parkend of 10 and 15 minutes respectively. If we allow a total of five minutes (guesstimate!) for stops at the intermediate stations of Lydney Town and Whitecroft, we then get an average speed of 12.6 mph (20.4 Kph). This is a nice leisurely pace at which to view to landscape of the Forest of Dean as it gently glides past the carriage window. Even more leisurely when sipping a cup of coffee at the same time!

As a point of potential interest, most UK heritage railways are subject to the Light Railways Act of 1896, which stipulated that the speed of 25mph (40.2 Km/h) should not be exceeded.

Map File

If you are keen to see the outline map of the DFR superimposed on an Ordnance Survey® (OS) map or on another system such as Google Maps®, then you can use the following file to do so. As mentioned above, the numerical data in this file have been hand-plotted by me on my return home. The data are based on WGS84. Of course, for copyright reasons, I do not show the OS-based or Google-based maps here.

And Finally

Any map is an approximate representation of what is, and my plotting thereon certainly is. Practicality and scale are relevant considerations. After all, we are not dealing with a planning application calling for detailed spatial descriptions of intricate boundaries. In this respect, I hope my humble endeavours on this page are interesting for, and useful to, you my reader!