1860 had been an important year for the LC&DR, and not just because of the commencement of through running between the capital and Canterbury. The company had also seen the "Metropolitan Extension Act" pass successfully through Parliament, which held the key to independent access to Victoria. The Act authorised a completely new route between Beckenham and Battersea via Herne Hill, and its advantages were two-fold: not only would the line allow the LC&DR to avoid costly track access payments to the LB&SCR, but it also gave rise to a new double-track spur to the City of London. For 2½-years, the LC&DR was subject to LB&SCR tolls over those metals originally opened under "West End of London & Crystal Palace Railway" auspices. This eventually came to an end in 1863 when, on 1st July of that year, the avoiding line via Herne Hill came into regular use. This had opened piecemeal:
Full opening of the line had been delayed by the Board of Trade, which decreed that spikes in the permanent way had to be replaced by wooden trenails. It was followed on 1st September 1863 by the LC&DR taking over the lease of the Mid-Kent Railway, which had previously been assigned to the SER. The double-track spur to Blackfriars came into use later, on 1st June 1864. Even the LB&SCR abandoned much of the original WEL&CPR line, save for local services, when it commissioned a shortened route between Balham and East Croydon on 1st December 1862.
Brixton station came into use with the Stewarts Lane to Herne Hill section of the LC&DR’s avoiding line in 1862. Perched high above the dense suburban landscape upon a series of viaducts, the site was positioned at the junction of the diverging Herne Hill and Crystal Palace routes. With reference to the latter, this opened on 1st August 1865 as a 6½-mile long branch line to rival the existing LB&SCR route, with services beginning at Ludgate Hill. It subsequently acquired an appendix at what became "Nunhead Junction", when a spur was opened to "Blackheath Hill" on 18th September 1871. Four platforms came into use at Brixton: two for the Herne Hill route and a pair for the line to Crystal Palace/Blackheath. Platforms were suspended above the streets, alongside the brick-built viaducts, upon a complicated series of iron struts, and the below arches were let out to local firms. The main building here was located within the fork of the diverging routes and was a structure of substantial size. Three-storeys high, the building comprised the familiar LC&DR crème/yellow brickwork, complete with orange-lined arched windows – these were features which could also be found on the equally large and contemporary main building at nearby Herne Hill. At platform level, the station building was surrounded on three sides by an attractive triangular-shaped canopy, which demonstrated a ridge-and-furrow roof, an ornate valance, and was supported upon cast-iron struts. Later cut back severely (more of later), a section of the original canopy design can still be seen today. Both outer platforms were also treated to the same style of canopy; in addition, these surfaces also boasted timber waiting shelters which, as per the platforms, were wholly suspended above the below streets upon iron struts. At ground level, the main building sprouted a further canopy on its eastern elevation, which hung over the entrance from the forecourt. Finally, the station was also subject to a name alteration: as early as May 1863, the name boards started to proclaim "Brixton & South Stockwell".
The maze of lines in the vicinity was completed by the opening of the South London Line by the LB&SCR. The full nine-mile-long circuit between Victoria and London Bridge came into use on 1st May 1867. The double-track line was carried over the LC&DR’s Herne Hill route, immediately east of Brixton station, upon a lattice girder bridge. Naturally, given the nature of the railway here, perched upon viaducts within a dense suburban setting, the absence of goods facilities was not surprising. However, this was perhaps made up for by the presence of an interesting signalling arrangement. To the west of the platforms, beyond the junction of the Crystal Palace and Herne Hill routes, existed an imposing three-storey-high brick-built signal tower. Comprising twenty levers, this dated from the station’s earliest years and was built up from ground level next to the "up" side of the double-track viaduct. A timber cabin projected from its northern elevation, but the "tower" was not unique: a virtually identical example also came into use at Loughborough Junction.