Over a distance of eight kilometres (five miles), the line climbs around a hundred metres (280 feet) to reach Maron, meaning a gradient of 1:75 and a severe test for engines on the North Western Railway.
Bankers are often required to help trains up the hill. However, they run the risk of being chased by a runaway train - something Duck found out the hard way.
When the railway was first built, this stretch was made even more difficult by strong winds blown in by the sea. This was attempted to be countered by the planting of trees on either side of the line, but in autumn there can be the additional risk of slippery leaves on the line, as James once discovered.
- In the fifteenth season episode, Big Belle, the hill was much steeper than usual.
- Since King of the Railway, there is a junction on the other side that goes to Ulfstead Castle.
- There is a real place in London called "Gordon Hill", but this is probably a coincidence.
- In the Railway Series, there are two sets of track on the hill, however in the television series, there are three.
- From the eighth season onwards, the bridge at the bottom of the hill is no longer shown and it doesn't curve as it goes down.