A walk around the block can take a few minutes or quite a lot of minutes depending on where you live. For me it takes ten minutes, where I grew up it took 30 minutes and for my brother it takes over an hour, such is the paucity of rights of way in Norfolk.
But what if we apply the concept of 'around the block' to the railways? How long does it take to go around the block by train, where's the smallest block in London, where's the largest block and how precisely do you define 'around the block' anyway?
Attempted definition: a 'ride around the block' brings you back to where you started on a circuit with no other railways inside the enclosed space. Important clarification: interchanges must be at stations - no walking inbetween.
Example: Green Park → Victoria → Westminster → Green Park is a ride around the block via the Victoria, Circle and Jubilee lines. The circuit is 4km long and encloses an area of about 180 acres.
The shortest 'ride around the block' on the tube
I think the shortest 'ride around the block' is Charing Cross → Leicester Square → Piccadilly Circus → Charing Cross. This triangular circuit is just under a mile long and encloses an area of about 20 acres. It's a teensy sliver of the West End with the National Gallery in the middle.
I walked it above ground.
Charing Cross → Leicester Square: I started on the edge of Trafalgar Square by the top of the steps down to the tube station. Admittedly all these entrances are closed at present because the Bakerloo ticket hall is shut, but that's only temporary. I walked north past St Martin-in-the-Fields and the National Portrait Gallery to the entrance to Leicester Square station. It took me 5 minutes. Leicester Square → Piccadilly Circus: I headed west along the edge of Leicester Square past the Lego store and all the cinemas. Coventry Street was full of tourists and tat and got even busier as I reached Piccadilly Circus. It took me 5 minutes. Piccadilly Circus → Charing Cross: This was harder to walk direct because the grid of streets doesn't align and the National Gallery gets in the way. It's thus the longest of the three sides of the triangle, weaving back towards Trafalgar Square. It took me 7 minutes. Total walk: 17 minutes
I also rode around the block underground.
Charing Cross → Leicester Square: It was a 2 minute hike down to the Northern line platform because this station is seriously spread out, having been optimised for a tube line that no longer stops here. I got unlucky because I just missed a train and the next was 3 minutes away. After all that faff and waiting, the tube journey only took a minute. So far that's 6 minutes. Leicester Square → Piccadilly Circus: It took a minute and a half to follow the side passage to the Piccadilly line. I got unlucky because I just missed a train and the next was 3½ minutes away. After all that faff and waiting, the tube journey only took a minute. So far that's 12 minutes. Piccadilly Circus → Charing Cross: It took a minute and a half to follow the side passage to the Bakerloo line. I got unlucky because I just missed a train and the next was 4½ minutes away. After all that faff and waiting, the tube journey only took a minute. Total ride: 19 minutes
I was surprised it was quicker to walk round the block than ride round the block, but I'd been unlucky by narrowly missing all three trains. If I'd just caught them I could have got the circuit down to eight minutes. That's how short this ride around the block is, the shortest in London and probably the shortest in the entire country.
The shortest tube rides around the block
I worked these out by looking at a tube map that just shows the tube with no additional extra lines. First I looked for small gaps with stations at all the corners. These were almost all in central London. Then I measured the length of all the circuits.
These are the ten smallest blocks I found.
1)1.4km Charing Cross/Leicester Square/Piccadilly Circus 2)1.6km Moorgate/Liverpool Street/Bank 3)2.2km Tottenham Court Road/Holborn/Leicester Square 4)2.4km Bond Street/Oxford Circus/Green Park 5)2.5km Oxford Circus/Green Park/Piccadilly Circus 6)2.6km Liverpool Street/Tower Hill/Aldgate East 7)2.7km Oxford Circus/Tottenham Court Road/Piccadilly Circus 8)2.8km Camden Town/Mornington Crescent/Euston 9)2.9km Oxford Circus/Tottenham Court Road/Warren Street 10)3.2km Baker Street/Bond Street/Oxford Circus
If you focus instead on the area inside the block, not the distance round the edge, the smallest block changes. It's now Liverpool Street → Tower Hill → Aldgate East because the only gap in the middle is the Aldgate Triangle with an area of about 2 acres. But this is quite complicated to measure and throws up all kinds of anomalies so let's stick with distances instead.
The longest ride around the block
Let's start by just considering the tube.
There are several huge loops in west London but they're all inadmissible because they don't have stations at the corners. The loop from Victoria south to Stockwell used to count but no longer does because the Battersea extension cuts across it. So we need to look to east London instead. The longest ride around the block on the tube turns out to be the Hainault Loop on the Central line. This is 20km from Leytonstone round to Hainault and Woodford, then back to Leytonstone again. That nudges into Essex, so if you want the longest ride around the block entirely within London it's Bank/London Bridge/West Ham/Monument at 18km long, which is just over 12 miles.
But we can do a longer loop within London if we consider all rail services, not just the tube.
The longest ride around the block ought to be the huge circuit from Clapham Junction to Richmond and Kingston and back again, all aboard one train, which is 30km long. However the District line intrudes inside this loop so I'm not allowing it. Instead the longest ride around the block is this loop in Greenwich and Bexley.
Start at Blackheath and wait for a Slade Green train. It's really going all the way round the Erith Loop and back towards London Bridge but they don't like to tell you that at this stage. Alight anywhere between Slade Green and Charlton and wait for a train back to Blackheath via the Blackheath Tunnel. The entire circuit is 29km long, that's 18 miles. I rode it yesterday and it took 1 hour and ten minutes, including quarter of an hour hanging around in delightful Slade Green. I'm not really sure why I bothered, other than to prove it was possible and take two photos, but I did get a lot of reading done on the train.
The Blackheath/Slade Green circuit encloses 35 square kilometres - that's 14 square miles. That's a very large central area with no other rail services, this because the rail network across Bexley is rather thin and the local population isn't well served by London standards. The loop round Richmond and Kingston encloses a larger area at 56 square kilometres, but a lot of what's in the middle is Richmond Park and deer don't catch trains.
If we look beyond London and consider the whole of the UK, I reckon these are the three longest rides around the block.
Perth/Inverness/Aberdeen: 512km (318 miles), enclosing 4300 square miles
Carlisle/Newcastle/York/Leeds: 472km (293 miles), enclosing 3000 square miles
Carlisle/Newcastle/Edinburgh: 463km (288 miles), enclosing 4000 square miles
But if we just stick to London the extremes are as follows:
The shortest ride around the block: Charing Cross/Leicester Square/Piccadilly Circus (1.4km) The longest ride around the block on the tube: the Hainault Loop (18km) The longest ride around the block within London: Blackheath/Slade Green/Blackheath (29km)
