Hamley Bridge is a community in South Australia located at the junction of the Gilbert and Light rivers, as well as the site of a former railway junction.

Named by the government of the day, in honour of the Acting Governor of South Australia Lieutenant-Colonel Francis Gilbert Hamley, whose wife, Lady Edith Hamley laid the foundation stone of the River Light Railway Bridge on 25 July 1868. This bridge carries the Peterborough railway line over the Light River.

Other settlements in the area had commenced in the early 1860s, and it was not until 1868 that the junction of the two rivers came under notice as a possible site for a township.

The Peterborough railway line was built from a new junction at Roseworthy (north of Gawler on what was then the Morgan railway line) to Tarlee during 1868. A bridge was required over the River Light. The bridge was 300 feet (91 m) long and 80 feet (24 m) high, in two spans on stone abutments and a cast iron cylindrical pier 6 feet (1.8 m) in diameter. This bridge was replaced in 1925 in conjunction with the works to convert the narrow gauge line to broad gauge, despite this bridge already being broad gauge.

Elevation is 374 feet (114 m).

The original railway through the town was 5 ft 3 in (1,600 mm). In 1880, a junction at Balaklava on the narrow gauge Port Wakefield railway line created the Balaklava railway line through Owen to meet the broad gauge line at Hamley Bridge. This was built to 3 ft 6 in (1,067 mm), so Hamley Bridge was a break of gauge station rather than a junction.

A new railway station was established a few hundred metres north of the original in 1880 and was at first known as Alma Railway Station.^{[citation needed]} The stone building, occupied as a private residence today, represents the fine architecture of the era and is heritage listed along with the signal box and water tanks, and two of the bridges over the River Light.^{[citation needed]}

As Hamley Bridge is only 40 miles (64.4 km) from the capital and major port, this break of gauge soon became a sore point, leading lobbying over decades to extend the narrow gauge all the way to the capital and that port. Trains reaching Hamley Bridge may have travelled 600 miles (965.6 km) from Oodnadatta, thus illustrating the poor design of this break of gauge. The break of gauge at Hamley Bridge was very cramped and poorly sited due to rivers, bridges, gradients and curves, which were difficult to improve upon. There were also shunting delays and a shortage of trucks. A counter proposal to ease congestion at the inadequate facilities at the Hamley Bridge break of gauge was to shift the break of gauge northwards to Balaklava, was strongly opposed. Alternately, the break of gauge may have been moved northwards to Owen