The line between Exeter and Plymouth was built and operated originally by the South Devon Railway Company.

It was constructed during the mid-to-late 1840s; its engineering was highly influenced by Isambard Kingdom Brunel, especially in the choice to incorporate a novel atmospheric railway propulsion system.

The line passed over to the newly-formed British Railways as a result of the GWR's nationalisation on 1 January 1948.

Brunel wielded considerable influence over both the planning and engineering aspects of the line, a factor that would lead to a controversial decision.

Other key figures within the company, such as the chairman Thomas Gill, were won over on the matter and the installation of atmospheric apparatus was approved.

[4] On 20 July 1847, the line was opened to passenger traffic from Newton to Totnes; the first goods trains followed on 6 December 1847.

[5] Initially, all trains running on the line were hauled exclusively by conventional steam locomotives; the first use of the atmospheric railway apparatus is believed to have taken place on 25 February 1847, immediately following the delivery of the first piston carriage.

Steam locomotives rapidly took over; on 10 September 1848, the final atmospheric-propelled train arrived at Exeter, after which the system was permanently deactivated.

A dispute with the Plymouth and Dartmoor Railway (P&DR) broke out where the two lines crossed paths on the route to Laira Bridge; after track had been laid without agreement, the P&DR responded by depositing large blocks of granite to temporarily block the route.

During 1977, the Parliamentary Select Committee on Nationalised Industries recommended considering electrification of more of Britain's rail network and, by 1979, BR presented a range of options to do so by 2000.

In the mid 1990s, the line was transferred from British Rail to the newly-formed private railway infrastructure company Railtrack, as part of privatisation.

The old South Devon Railway main line,[22] crosses the River Exe and a parallel flood relief channel, and then passes above the suburbs of Exeter along a stone viaduct on which is situated Exeter St Thomas railway station.

[27] Beyond Parson's Tunnel is a short viaduct across Smugglers Lane and then the footpath resumes alongside the line for the final stretch of the Sea Wall past Sprey Point to the cutting at Teignmouth Eastcliff.

On the right side of the railway near Sprey Point can be seen the remains of a lime kiln used during the construction of the line.

[24] The railway passes under the long Shaldon Bridge and then follows the river past the small promontories at Flow Point, Red Rock, and Summer House.

The line from Exeter to Plymouth was designed by Isambard Kingdom Brunel as an atmospheric railway which allowed steeper gradients, sharper curves, and lighter structures.

Atmospheric trains never ran beyond Newton Abbot yet the legacy of the aborted scheme means that line speeds on towards Plymouth are lower than elsewhere on the route.

The line immediately crosses over the River Dart and arrives at Totnes, which has passing loops to allow slower trains to be overtaken.

The steep climb up Rattery Bank starts right from the end of the platform, a stiff challenge in former days to trains that called at Totnes.

275 yards (251 m) Slade Viaduct brings rises to the top of Hemerdon Bank, the steepest climb for trains heading towards Newton Abbot.

The large goods yard here includes a maintenance shed for on-track equipment and a connection to the china clay drier at Marsh Mills.

Underneath the Embankment Road bridge which carries the A38 over the line again and Laira TMD on the left.

These services include the high speed trains from London Paddington to Penzance, Plymouth or Paignton.