After running the Central Line last year I wanted to run another Underground Line. This Saturday worked well, with the weather improving (beginning of spring) and being in shape for such a long run (having done some training, being due to race an ultramarathon that got cancelled at the last minute, with this FKT being an opportunity not to waste that training). I was already familiar with most the areas covered by the Northern Line but it was an interesting opportunity to connect them all in one go and experience the diversity of landscapes and communities London has to offer.
Unlike the Central Line that stretches all the way to Essex, Northern Line felt more urban. With all the traffic and traffic light stops you'd expect. The start was undulating, but roughly downhill overall which made it feel easy and good as a warm up. I fell in very familiar ground when I reached the Highgate area (where I do much of my hill training) and obviously central London. The Northern Line has many branches, the first big one was the 'via Bank' you can hear often (and should check) when taking the Tube. Being a Saturday, the City (section between Old Street and London Bridge) was very quiet. London Bridge/Borough Market was busy as expected and it got quiet again when doing the long (and not so inspiring) stretch to the southern end of the line at Morden, and back again. With one marathon in the legs, Morden was the half-way point. Refilling my water flasks was easy, with the many water fountains by the stations along the way (shaped like a large blue drop - the locations can be found on https://apps.london.gov.uk/water-fountains). This route include the newest branch (Battersea Power Station) opened just a few years ago. While the run had been fairly smooth so far, it got messy once reaching Waterloo. Central London was packed and running through the crowds of the West End, and later Camden, was a chaotic experience. My pace went all over the place trying to dodge people and I lost my rhythm. It got hard to get it back later on. The 'via Charing Cross' branch shouldn't be attempted on a Saturday afternoon! It got quiet again when leaving Camden. Just the biggest hill of the route (Hampstead) to fight against on tired legs and the finish was near with Edgware not too far behind.
The run was unsupported, thanks to the water fountains mentioned above, a few gels and Snickers I kept in my hydration vest.