Hastings line
Introduction


The **Hastings line** is a secondary railway line in [Kent](/wiki/Kent "Kent") and [East Sussex](/wiki/East_Sussex "East Sussex"), England, linking  with the main town of , and [London](/wiki/London "London") via  and . Although primarily carrying passengers, the railway also serves a [gypsum](/wiki/Gypsum "Gypsum") mine which is a source of freight traffic. [Southeastern Trains](/wiki/Southeastern_%28train_operating_company%29 "Southeastern (train operating company)") operates passenger trains on the line, and it is one of their busiest lines.

The railway was constructed by the [South Eastern Railway](/wiki/South_Eastern_Railway%2C_UK "South Eastern Railway, UK") in the early 1850s across the difficult terrain of the [High Weald](/wiki/High_Weald "High Weald"). Supervision of the building of the line was lax, enabling contractors to skimp on the lining of the [tunnels](/wiki/Tunnel "Tunnel"). These deficiencies showed up after the railway had opened. Rectifications led to a restricted [loading gauge](/wiki/Loading_gauge "Loading gauge") along the line, requiring the use of dedicated [rolling stock](/wiki/Rolling_stock "Rolling stock").

Served by [steam locomotives](/wiki/Steam_locomotive "Steam locomotive") from opening until the late 1950s, passenger services were then taken over by a fleet of [diesel\-electric multiple units](/wiki/Diesel-electric_multiple_unit "Diesel-electric multiple unit") built to the line's loading gauge. [Diesel locomotives](/wiki/Diesel_locomotive "Diesel locomotive") handled freight, also built to fit the loading gauge. The diesel\-electric multiple units served on the line until 1986, when the line was electrified and the most severely affected tunnels were reduced from [double track](/wiki/Double_track "Double track") to [single](/wiki/Single_track_%28rail%29 "Single track (rail)").


What is the consequence of these deficiencies for the loading gauge along the line?