The line was built after the First World War to serve sand quarries north of the town.

A bed of Lower Cretaceous sand across Bedfordshire has been quarried on a small scale for centuries.

In the 19th century sand was carried by horse carts from quarries south of the town to be shipped on the Dunstable-Leighton Buzzard railway.

The carts damaged roads and resulted in claims for compensation against the quarry owners from Bedfordshire County Council.

After 1919 the quarry companies were told they could no longer transport sand by roads, so a private industrial railway was proposed to take the traffic.

From that point the railway was run using internal combustion, almost exclusively the products of the Motor Rail company.

The BR line to Dunstable was closed in 1965, apart from a short stretch from Leighton Buzzard to Grovebury interchange sidings, which survived until 1969.

In November 1966 "The Iron Horse Railway Preservation Society" was formed with the objective of running passenger services on the line.

They ran their first excursion on 3 March 1966. using two Simplex locomotives at each end of a train of three bogie wagons borrowed from the railway.

This was undertaken, the group having purchased secondhand rolling stock and four Simplex diesels from the St Albans Sand and Gravel company, which were dismantled and formed into one machine.

On the left is the site of Marley's Tile Works, now a housing estate, which was connected to the railway for most of its existence.

At the bottom of Marley's Bank the line turns sharply north and runs along the level to Leedon Loop.