A drilling machine invented by Colonel Beaumont of the Royal Engineers was used to bore a pilot hole through the rock under the river and the main tunnel was excavated manually with explosives and picks and shovels.
The original line ran from Green Lane in Birkenhead to James Street in Liverpool. It was opened by the Prince of Wales (later to become Edward VII) in 1886. In 1888 a branch line to Birkenhead Park was built and, in 1891, the Green Lane line was extended several miles to Rock Ferry.
By 1890, the tunnel was carrying over 10 million passengers a year but there was still competition from the combined services of the surface electric trams and the ferry from Woodside, which many people thought to be considerably healthier than breathing the steam and smoke-laden fumes on the underground railway. To combat this, in 1903, the Mersey Railway became the first steam railway in the world to change over entirely to electric power.