The rival London and South Western Railway (LSWR) sought to reach Plymouth too; it planned an approach by a northern alignment from Exeter through Okehampton, encouraging the friendly Devon and Cornwall Railway Company to build the line; the LSWR took the smaller company over on 1 January 1872.

Although this was a disappointment, it enabled other tactical agreements to be made with the SDR company, and avoided a difficult Parliamentary battle; as part of the agreement that the D&CR would abandon certain authorised extensions, the SDR granted running powers over its line between Lidford and Devonport, and agreed to build a connecting line in Plymouth (the Cornwall Loop) and a Plymouth station at North Road.

The PD&SWJR bill was successful, receiving royal assent as the Plymouth, Devonport and South Western Junction Railway Act 1883 (46 & 47 Vict.

[3] The construction of the main line posed significant engineering challenges due to the difficult terrain, and it took some time to gain the necessary subscriptions; the first sod was not cut until 29 March 1887.

The Tavistock station was intended to be at the Launceston road on the northern margin of the town, but local people presented a petition and were successful in altering its location, costing an additional £2,000 due to the need to build special access arrangements.

The need to enter the Devonport terminus from the west end, through a residential area, posed particular difficulties, as did the tidal mud inlets in the southern section.

On 1 July 1891, the LSWR Friary passenger terminus was opened; when running over the SDR Tavistock line, LSWR passenger trains arriving in the area had run through Plymouth from east to west, calling at the GWR Mutley and Plymouth North Road stations, and terminating at the Devonport terminus.

[3] The LSWR energetically developed suburban traffic in the greater Plymouth area, running a relatively frequent stopping service between Friary and St Budeaux.

The rise of street-running passenger tramways in Plymouth from 1872 posed a competitive threat, and this accelerated when electric trams were introduced in 1899.

The LSWR responded by introducing railmotors, single passenger coaches with an integrated steam power unit, on 26 September 1906, with additional halts opened on 1 November that year.

Nonetheless street-running public passenger transport achieved gradual dominance, and the LSWR found that outer suburban services were more beneficial.

[7][8] Remote from the other main Southern Railway constituents, the PD&SWJR route was not outwardly affected by the organisational change.

Multiple part passenger trains from London had traditionally favoured Plymouth as the prime destination, but this emphasis was altered.

On 20 June 1947, the Southern Railway instituted the Devon Belle, an all-Pullman train running between Waterloo and Plymouth, with an Ilfracombe portion.

[2][3] The general increase in road use led to a steep decline in use of the line in the 1950s, and closure of parts of the route came under consideration.

Following the report the Reshaping of British Railways published in 1963 led to the so-called Beeching cuts, which resulted in the suspension of the Atlantic Coast Express trains after 5 September 1964, the PD&SWJR route being reduced to the status of a secondary line.

The remainder of the PD&SWJR lines continues in operation, with a local passenger service from Plymouth to Gunnislake.

Their leading dimensions were: The Hawthorn Leslie locomotives were blue with brass dome covers and chimney caps.

They were repainted in SR livery between March 1926 and April 1927, and their LSWR numbers were prefixed with the letter E, denoting Eastleigh Works, which had been responsible for their maintenance following the cessation of repairs at Callington Road in mid-1923.

[10] The Exeter - Newton Abbot main line via Dawlish was severed for several weeks by extreme weather in early 2014, and it has been suggested that the entire Exeter - Crediton - Okehampton - Tavistock - St Budeaux line should be reconstituted as an emergency diversionary route, in case of a repetition.