The branch line was 8.2 miles long from Harpenden Junction to Hemel Hempstead
Gas Works. There were sidings at Redbourn, Owen's Sidings, Hemelite Company
at Cupid Green (formerly Claydales Brickworks), Godwins Halt,
Hemel Hempstead (Midland), Cotterells Sidings and Hemel Gas Works.
Originally trains commenced their journey at Luton and
joined the branch line at Harpenden Junction which was
at that time located further north of the position shown
on the map here. The original cutting curved
towards Luton from the branch, but in 1888
a south-facing curve was installed to
take trains onto the mainline and
into Harpenden Station
allowing quicker travel
to London

With the removal of the track south of Hemel Hempstead (Midland) Station a connection was laid between Hemel Gas Works and Hemel Hempstead & Boxmoor Station to allow
coal to be delivered until the Gas Works finally closed in 1960.