Portsmouth line

Sutton and Epsom were first reached by an extension of the London and Croydon Railway (L&CR) from West Croydon. This was promoted by the L&CR as an independent company, the Croydon and Epsom Railway (C&ER), and was originally proposed to be an atmospheric railway.

In 1846 the C&ER merged with the L&CR, the London & Brighton Railway and others to form the LBSCR, and in 1847 the Croydon and Epsom route was completed as a conventional locomotive-hauled line under LBSCR auspices. It ran via Wallington, Sutton, Cheam and Ewell to an Epsom station on the east side of town.[2]

Twelve years later the independent Epsom and Leatherhead Railway (ELR) built a line from a new station on the west side of Epsom to Leatherhead, opening in February 1859 as single line with just one intermediate station, at Ashtead. The LSWR-promoted Wimbledon and Dorking Railway connected end-on at Epsom, opening in April 1859. On 8 Aug 1859 the LBSCR opened an extension from its existing Epsom station to the ELR. Within a year the ELR was jointly acquired by the LSWR and LBSCR.

The original Epsom and Leatherhead junctions (after the opening of the Bookham Branch) with separate LBSCR and LSWR stations in both towns.

A single-line branch from the Brighton Main Line at Three Bridges to Horsham, later known as the Mid-Sussex Line, had opened in 1848. It was extended down the Arun Valley to Petworth via Pulborough in 1859 (eventually reaching Midhurst in 1866). In 1862 it was doubled throughout, and the following year it was extended from Hardham Junction, south of Pulborough, to Arundel Junction on the West Coastway Line. This, in 1863, gave the LBSCR a more direct path from London to Chichester and Portsmouth than the long detour via Brighton, although it followed two-thirds of the Brighton Main Line before turning cross-country.

In 1862 the Horsham, Dorking and Leatherhead Railway (HDLR) was authorised to provide a link from the Mid-Sussex Line at Horsham to Leatherhead, crossing the North Downs via the Mole Valley between Dorking and Leatherhead. The line connected to the ELR at Leatherhead, just east of the existing station. At Dorking there was a south-to-west spur to the South Eastern Railway's Reading, Guildford and Reigate Railway,[3] but this was never used for regular services.

When the HDLR opened in 1867 it created an LBSCR route to Portsmouth that avoided much of the busy Brighton Main Line, although it was actually longer than the Mid-Sussex/Arun Valley route,[note 6] and still used the congested lines through Norwood Junction and Selhurst.

So far the LBSCR route to Epsom and beyond had been via the Wallington (West Croydon to Sutton) line but in 1868, only a year after the Horsham to Leatherhead connection, they opened a line from Peckham Rye to Sutton via Tulse Hill and Mitcham Junction. Although it primarily filled gaps in the LBSCR suburban network it also improved the route to Portsmouth, being slightly shorter than via Wallington,[note 7] and bypassed the bottlenecks at Norwood Junction and Selhurst; so it was promoted as a new "Portsmouth Line".

Peckham Rye, Tulse Hill and Streatham Junctions in 1914

On opening in 1868 the Sutton line had many links, all but one to other LBSCR lines:

• A branch from the Chatham Main Line (LCDR) at Herne Hill to Tulse Hill
• Chords from Tulse Hill up to the Crystal Palace Line in both directions
• The Brighton Main Line junctions at Streatham:
  • a double-track SW to SE chord from Streatham (Streatham Junction) down to the Slow Lines at Streatham Common
  • a double-track flying junction SE to SW from the Slow Lines (Streatham North Junction) to the Portsmouth (Streatham South Junction)
  • a separate single-track chord with crossovers up from the Fast Lines
• The Wimbledon Loop branching off west at Streatham South Junction
• Crossing the Wimbledon and Croydon Railway at Mitcham Junction
• At Sutton the line from West Croydon via Wallington joins in a trailing direction, and the Epsom Downs Branch turns away to the south

The section from Peckham Rye to Streatham passes through the grounds of Dulwich College and relatively hilly terrain, which required some costly engineering works:

• A brick-lined cutting leading to North Dulwich station
• An ornate brick-arch viaduct through the College grounds, with several cast-iron road overbridges[4]
• Knights Hill Tunnel
• Leigham Tunnel
• Streatham Tunnel

The arches of the viaduct and the south portal of Knight's Hill Tunnel are adorned with the monogram "AC", in tribute to the landowner Alleyn's College, as Dulwich College was known at the time the line was built.

Mitcham Junction station is approached from both directions by severe curves that turn the Portsmouth Line through 90-degrees to join the alignment of the Wimbledon-Croydon line (running NW-SE), then back to resume it's broadly SW alignment.[note 8]

Inside the LSWR Leatherhead station, when it was a through station on the Bookham branch

In 1885 the LSWR opened the New Guildford Line from Surbiton to Guildford via Cobham. This included a branch from Effingham Junction[note 9] via Bookham to the Portsmouth Line at Leatherhead. This turned the old LSWR terminal at Leatherhead into a through station, and enabled a "Guildford via Epsom" service which continues to this day.

After the Grouping, in 1927 the Southern Railway diverted the Bookham line to join the HDLR to the west of the LBSCR station, which then became the only Leatherhead station. A stump of the original ELR/LSWR line was retained for carriage sidings.

Also in 1927 the Southern Railway completely rebuilt Epsom LSWR station and layout to give the LBSCR (Sutton) line access to the platforms. Epsom Town was closed to passengers in 1929, and became the main goods station for the area, relieving the cramped yard at Epsom (LSWR).

One of the last new lines to be built in Britain before the HS1 era was the Wimbledon and Sutton Railway (W&SR), from Wimbledon through Merton and Morden, to join the Portsmouth Line in the up direction south of Sutton. Construction began in 1927[note 10] and was completed in 1930. The Wimbledon & Sutton line is now part of a circular route from Streatham, via the Portsmouth Line to Sutton, the W&SR to Wimbledon, then the Wimbledon Loop (northern branch) back to Streatham.

There are five tunnels, built between 1860 and 1867:

Knight's Hill Tunnel, 331 yards (303 m) long, between North Dulwich and Tulse Hill has a very ornate southern portal, surmounted by the arms of Alleyn's College, the local landowners.[5] The southern portal is framed by pilasters on each of which are two ball finials (stone spheres); it can be seen from Tulse Hill station. The northern portal, which is hidden in a cutting, is quite plain.

Leigham Tunnel, 302 yards (276 m) long, is between Tulse Hill and Streatham Tunnel. It is also called Higher Leigham or Leigham Vale Tunnel[6] to distinguish it from Leigham Court Tunnel on the Crystal Palace Line between Streatham Hill and Leigham Junction.

Streatham Tunnel, South Portal

Streatham Tunnel, 220 yards (200 m) long, between Leigham Tunnel and Streatham station. It is on a curve and most unusual in that the southern portal is a skewed arch, with decorative details including massive stone capping, dentils and panelled brickwork.[7]

Mickleham Tunnel is midway between Leatherhead and Box Hill & Westhumble. It is 524 yards (479 m) long and runs through the lower chalk of Norbury Park, entering the hillside immediately north of one of the three viaducts over the River Mole.[8] Restrictions imposed by the landowner, Thomas Grissell, meant that vertical ventilation shafts could not be constructed. The tunnel portals were given lavish architectural treatment.

Betchworth Tunnel is 0.25 miles (0.40 km) south of Dorking. It is 385 yards (352 m) long with a maximum gradient of 1 in 80 (1.25 per cent). It runs through the upper greensand of the Deepdene Ridge to the east of the town. Construction difficulties delayed the opening south of Dorking. It collapsed on 27 July 1887, remaining closed for over six months.[9]

The viaduct across the grounds of Dulwich College already mentioned includes some decorated cast-iron underbridges: West Dulwich, Croxted Road Bridge (image 5).

Between Leatherhead and Dorking are a number of brick-arch viaducts over the River Mole, not as elaborate as the Dulwich viaduct but still notable: River Mole viaducts, images 3-5. Mickleham Tunnel exits directly onto one of them.

ELR Plate showing BTH1 mileage at Mitcham Junction

The Portsmouth Line is most of the Line of Route (LOR) SO680, Bermondsey Junction to Horsham, although that also includes part of what was historically known as the South London Line,[note 11] from South Bermondsey to Peckham Rye.

Because of the fragmentary origins of the Portsmouth Line, for engineering purposes it comprises several distinct sections with different mileage origins. Corresponding to LOR SO680 is the Engineer's Line Reference (ELR) BTH ("Bermondsey to Horsham"), which is divided into 3 sections with mileage breaks at Sutton and Epsom.

The route from the two LBSCR London termini to Portsmouth uses various other ELRs. The following table describes the complete routes from London Bridge and Victoria to Portsmouth Harbour,[note 12] with the Portsmouth Line itself highlighted in blue[10]

• London Bridge to East Croydon and beyond via Streatham and Selhurst
• London Bridge to West Croydon and beyond via Tulse Hill and Crystal Palace
• Victoria to Dorking and Horsham via Mitcham Junction, Sutton and Epsom

Epsom Downs services usually run via Wallington and only interchange with the Portsmouth Line at Sutton.

Sutton Station in 1905.

• Waterloo to Dorking via Epsom
• Waterloo to Guildford via Epsom

• Luton or St. Albans to Sutton via Wimbledon (Sutton Loop anti-clockwise)
• Luton or St. Albans to Sutton via Mitcham Junction (Sutton Loop clockwise)

Thameslink Sutton Loop services join the Portsmouth Line at Tulse Hill. The Thameslink Peterborough to Horsham service runs via Three Bridges.