In 1872 the Northampton and Banbury Junction Railway (from 1910 part of the Stratford-upon-Avon and Midland Junction Railway (SMJR)) was opened between Blisworth and Farthinghoe.
It passed roughly east–west along the Tove Valley through the middle of the village, where its Helmdon station was opened.

In the 1890s a civil engineering contractor, Walter Scott and Company of Newcastle upon Tyne, built the section of the Great Central Main Line (GCML) between Woodford Halse and Brackley Central.
From 1894 to 1898 Scott had a construction yard in the Tove Valley at Helmdon with a network of sidings connected to the SMJR.
It was next to where the company built Helmdon Viaduct, a nine-arch structure of Staffordshire blue brick that carried the GCML main line across the valley.

The main line linked northern England with London Marylebone and opened in 1899.
It ran roughly north–south through the parish, passing just west of the village.
There the Great Central Railway (GCR) opened its own Helmdon station, causing some confusion with the SMJR's existing Helmdon station.
In the 1920s Sulgrave Manor House, about 2 ¹⁄₄ miles (4 km) from Helmdon, was restored as a museum to the family of George Washington, whose ancestors held that manor from 1540 to 1659.
In response the London and North Eastern Railway, which had succeeded the GCR in 1923, renamed its main line station "Helmdon for Sulgrave" from 1928.

British Railways closed the SMJR station and line in 1951, the GCML main line station in 1963 and the main line in 1966.
Helmdon Viaduct survives.
In 1872 the Northampton and Banbury Junction Railway (from 1910 part of the Stratford-upon-Avon and Midland Junction Railway (SMJR)) was opened between Blisworth and Farthinghoe. It passed roughly east–west along the Tove Valley through the middle of the village, where its Helmdon station was opened.
In the 1890s a civil engineering contractor, Walter Scott and Company of Newcastle upon Tyne, built the section of the Great Central Main Line (GCML) between Woodford Halse and Brackley Central. From 1894 to 1898 Scott had a construction yard in the Tove Valley at Helmdon with a network of sidings connected to the SMJR. It was next to where the company built Helmdon Viaduct, a nine-arch structure of Staffordshire blue brick that carried the GCML main line across the valley.
The main line linked northern England with London Marylebone and opened in 1899. It ran roughly north–south through the parish, passing just west of the village. There the Great Central Railway (GCR) opened its own Helmdon station, causing some confusion with the SMJR's existing Helmdon station. In the 1920s Sulgrave Manor House, about 2 ¹⁄₄ miles (4 km) from Helmdon, was restored as a museum to the family of George Washington, whose ancestors held that manor from 1540 to 1659. In response the London and North Eastern Railway, which had succeeded the GCR in 1923, renamed its main line station "Helmdon for Sulgrave" from 1928.
British Railways closed the SMJR station and line in 1951, the GCML main line station in 1963 and the main line in 1966. Helmdon Viaduct survives.
Helmdon