tubechallenge.com

Forget running. Forget time tables. This is map-oriented challenge.

What is the maximum number of different stations you can visit?

Provided:
* You can only visit (or pass through) each station once.
* You must change within LU stations (e.g. you can't change between Bank and Monument since these are different stations. The same goes for the two Hammersmiths etc).
* No non-LU routes allowed (such as rail, bus or DLR).
* Both start and end stations are counted.

Let's start by only submitting numbers (no routes) to this thread!

I have a route with 100+ stations...

Good luck!

Ha Ha methinks you have too much spare time on your hands

Am very close to 100 after one attempt.

Nice challenge. TFL can't screw this one up on the day

And now way over 100.

I'm sure that as this is a true network problem, you can rustle up a quick program to solve this Hakan?

I beleive I could [write a program]...

However, I've found a 119 solution by hand and it looks close to perfect - but I'm far from certain!

Rather than working out a route, I figured I'd try and work out a theoretical maximum for the number of stations and gradually reduce it. To paraphrase Radiohead - you go forwards, I go backwards, somewhere we will meet...

There are 123 stations that aren't on a 'dead end', as shown on this map that I've hacked up (hello there, friendly LU lawyer!). The longest dead ends are Warwick Avenue to Harrow & Wealdstone (13 stations) and Leyton to Epping via Hainault (18 stations) so if you were to start at Harrow & Wealdstone, somehow do all 123 stations and emerge at Epping, that would give you a total of 154.

That's not to say that 154 is actually possible - you can't visit Ealing Broadway, Acton Town and North Ealing without either revisiting Ealing Common or finishing at one of those stations, for example. Will work at whittling down the maximum figure some more...

hwolge wrote:However, I've found a 119 solution by hand and it looks close to perfect -

I got 117 with my first attempt, time to find those two elusive stations!

editorsfoot wrote:time to find those two elusive stations!

Found them, I've got 119 too!!

And I *think* I've reduced the theoretical maximum to 144 through a rather messy algorithm: if we make the optimistic assumptions that

• we're able to take the longest possible dead ends (H&W and Epping) as the start and end points
• we're able to visit all the interchanges
• at each interchange we're able to take the longest possible route to the next interchange

then we can draw a graph of all the interchanges plus H&W and Epping, look at each station separately, and pick the longest route to the next (unless we've already picked it in the other direction). Then add together the lengths of the routes, add 1 for the starting station, and by my count you get 144.

I too have found 119, staring at Epping and finishing at Wimbledon. The bit in between is top secret...

Soup Dragon wrote:I too have found 119, staring at Epping and finishing at Wimbledon. The bit in between is top secret...

Well that's different to my 119 which started at Harrow & Wealdstone and Finished at Epping. Does this mean 119 is some significant number for tube challengers?

I just found another route, 124 stations, starting at Epping again, but finishing at Heathrow T123... beat that !!!

Actually it gets better... I've just found 125, and I promise you there are no ******** tactics being used...

This was more interesting than I thought. My 119 started at Epping and finished at High Barnet!!

I gues I'll have to look further into it now.

gasman wrote:Leyton to Epping via Hainault

How I wish that was actually a service!