The London and Southampton Railway reached Northam in 1839. In order to continue to Southampton Terminus railway station the line had to cross Northam road. Originally a level crossing was constructed but after a dispute with the Northam bridge company the railway agreed to build a bridge to carry the road over the railway. Construction of the bridge in brick began some time before 1840. In 1858 new junction was added connecting the line to what is now Southampton Central railway station. This required the extension of the bridge which was done by added a cast iron section