The North London Line runs on a roughly semi-circular path through the suburbs of west, north and east London from Richmond in the southwest to North Woolwich in the southeast.
The line is double track with the exception of the eastern section which is singled beyond Custom House down to the North Woolwich terminus. In addition the line is either tripled or quadrupled along parts of the northern section between Camden and Western Junction to help accommodate the large number of inter-regional freights crossing this part of London en route to destinations throughout the UK and Europe.
There are 28 stations along the line's 22 mile route including links and interchange facilities with a myriad of other lines, both passenger and freight. So useful has the line become as a connecting service that it was added to the London Underground map in the 1990s.
Passenger services are provided by Silverlink trains (originally known as North London Railways following privatisation) using 3-car class 313 multiple units exclusively, due to the mix of overhead and third rail power supplies along the route.
Planned upgrading of the line will result in a doubling of the current maximum of 4 passenger trains per hour to 8 at peak as well as providing platform accommodation for 6-car units at all stations.
However, on this line, freight normally travels faster than passengers.
I came to know the line in the late 60s and early 70s when I used it frequently, although during that period its easterly terminus was Broad Street in the City. In those days, in addition to the NLL services to Richmond, peak-hour commuter trains to and from GN destinations such as Hertford and Potter's Bar also ran from Broad Street utilising both DMUs and loco-hauled non-corridor stock.
On weekday afternoons Finsbury Park shed would send down a train of three locomotives (usually 1 EE and 2 Brush type 2s) to Broad Street, via the now freight-only link at Canonbury West Junction, to help work these commuter services north during the evening rush hour.
Broad Street station dates back to 1865 and was once the third busiest in London, with a train a minute arriving or departing during the morning peak in the early part of the twentieth century. Broad Street's busiest year was 1902 when the station's nine platforms handled 27 million passengers (similar to current volumes at Euston).
As a result of the growth in alternative transport systems, coupled with the serious damage sustained by the terminus during World War II bombing raids, the main part of the station was closed in 1950. By the late 60s only two platforms remained in regular use handling the North London Line services to Richmond. Final demolition of Broad Street was completed in 1986.
Sadly, all traces of the old station have since been swept away and the site is now occupied by the massive Broadgate office and shopping complex.
Following the demise of the former terminus the line up to Western Junction, including the large (originally 6 platforms) Dalston Junction station, was closed. Today's NLL trains, instead of turning south at Western Junction for the run down to Broad Street, continue eastward through the junction towards the current terminus at North Woolwich.
The new route runs initially over the former NL connection to the docks, thence via GE tracks beyond Victoria Park and finally onto the former Eastern Counties branch to North Woolwich. Part of this route was in fact used during the earliest days of the line, which, prior to the opening of Broad Street in 1865, had its City terminus at Fenchurch Street (dating from 1854).
Plans are currently in hand to revive all but the southernmost section of the former Broad Street - Western Junction trackbed (virtually untouched due to being located primarily on urban viaduct along most of the route) as part of the proposed northern extension to the old Metropolitan East London Line.
The intention is to extend the ELL from its present northern terminus at Shoreditch north to Highbury & Islington, a station which has continued to grow in importance as an interchange hub over the years, particularly for commuters between the City and the Northern suburbs. Following the opening of the extension, the existing ELL station at Shoreditch will be replaced by a new station at Shoreditch High Street.