With his experience of military surveying, Moorsom assisted in the construction of the London and Birmingham Railway construction of which had begun in 1833 and of which his eldest brother, Constantine Richard Moorsom was Secretary to the Board. Moorsom's survey of the valley of the Ouse allowed the railway line to be straightened, and eliminated the need for a large embankment. This feat attracted the attention of Robert Stephenson. He then spent two years studying new railway lines all over the country and in 1836 undertook a survey of the country between Birmingham and Gloucester in order to build a railway. The Birmingham and Gloucester Railway had found Brunel's proposals out of its financial reach. Moorsom's brief in 1836 was to build the line as cheaply as possible, which he did by following open country, thereby avoiding populated areas where land prices were higher. Arriving at the Lickey Hills there was no option but to climb, using cable assistance if necessary.