By around 1890 major changes to the area had taken place and it was planned to divide up the main square of the Kensington Gore estate. Imperial Institute Road and Prince Consort Road (labelled as the proposed new road, in yellow on the plan) were laid out in 1892 straight across the site of the Royal Horticultural Society (RHS) Gardens, which had been closed in 1882.
The Imperial Institute (coloured in orange on the plan) took over most of the central section of the former gardens, with the Royal Albert Hall in the top most part. The newly opened Natural History Museum occupied the southernmost section, along with the South Galleries (coloured in green) of the South Kensington Museum.
The pneumatic railway
This plan of c.1890 is particularly interesting for the inclusion of the subway along Exhibition Road. South Kensington Underground Station opened in 1868. The uphill approach to the hall from the station was served by buses of the Metropolitan Railway for a few years. In the 1870s there was a scheme for an underground pneumatic railway to link the station to the hall, but this never got funds.
Until the late 1880s much of the pedestrian route from the station to the top of the estate could be taken under cover, through the arcades of the gardens. Once the gardens closed the only option for a weather-proof route was via a subway.
The pedestrian subway (dark grey) opened intermittently in 1885 for a toll. As can be seen on this map the subway had been built up to almost level with Imperial Institute Road. This was where an entrance to the RHS Gardens had been, and today it is the subway exit near the Science Museum. It was planned to extend the route (red) up to the hall, but once again this failed to get funding. From 1908 the subway was opened permanently and free of charge.