Is the "Only One Tunnel in London" achievement even POSSIBLE?

[kschang77]

Even the three beginning stations often require you to build two tunnels just to connect them at all!

[Quivico]

Um, in London? There's only one river, and no islands, so you can survive with one tunnel.

[socks.]

This is something we've noticed, but on the most part hasn't stopped the achievement from being possible so we've not made any changes to the map itself.
While there are some starting configurations that make it impossible to achieve without waiting for another station to spawn, in those scenarios all I can suggest is restarting before getting too invested.
Hope it doesn't cause too much frustration, good luck!
~ Tom

[RobOda]

Originally posted by (Pogo):

This is something we've noticed, but on the most part hasn't stopped the achievement from being possible so we've not made any changes to the map itself.
While there are some starting configurations that make it impossible to achieve without waiting for another station to spawn, in those scenarios all I can suggest is restarting before getting too invested.
Hope it doesn't cause too much frustration, good luck!
~ Tom

Does the achievement become void the moment a second tunnel is placed? Or can we delete them later? :)

[DoubleDoom]

Yes, it is possible. Did this one fairly easily. You just have one line dedicated to north/south

[kschang77]

Originally posted by Quivico:

Um, in London? There's only one river, and no islands, so you can survive with one tunnel.

Yeah, except there's U-shape river... If it's STRAIGHT river, it'd be easy-peasy.

[Davypi]

Beacause of this thread, I went an unlocked this last night in under 20 minutes. So to answer some questions....

It is possible. As pointed out, there is only one river, so there is nothing about the topology that inherently prevents the achievement. However, as also pointed out, if one of your early stations ends up inside the U bend it could be difficult or impossible.

The game doesn't appear to count a tunnel as built until you've actually let go of the mouse. During a couple of my builds I accidentally created a tunnel and was debited, but I hadn't release the mouse. So I backed up and built something else and was still able to obtain the achievement.

What I didn't try was destroying my tunnel and building a different one, so its not clear if the one tunnel rule means only one specific tunnel for the whole game or just one tunnel at any given point in time.

Strategy wise, placement of upgraded stations seems to be important. Since unique symbols appear on both sides of the river, you need the stops on each side of the tunnel to load/unload quickly. (I also didn't get any square stations south of the river, so I also had to move my square passengers across quickly.)

[RobOda]

My achievement popped on a different map by mistake it seems. Oh well.

[Catratio]

I got it the other night but it took a few tries. Have one central north-south line and opt for new lines so you can branch them out at the top and bottom of the map as needed to avoid having to build new tunnels. I did have to restart once due to bad/impossible station spawning right at the start so some luck is required.

[rose.mark]

I got it without specifically trying for it on the alternate London (1960) map.

[Proxy Kaizen]

I had to restart a few times to get this achievement, because it will put a location you cannot get to without going over the water a second time. The way around this is to wait and hope that it puts an adjacent location, from which you can "elbow" around the river instead. random number generation.

[Run The Jewels]

Just did this one right now. https://steamcommunity.com/sharedfiles/filedetails/?id=1373412377

[Joachim]

Originally posted by Davypi:

Beacause of this thread, I went an unlocked this last night in under 20 minutes. So to answer some questions....

It is possible. As pointed out, there is only one river, so there is nothing about the topology that inherently prevents the achievement. However, as also pointed out, if one of your early stations ends up inside the U bend it could be difficult or impossible.

The game doesn't appear to count a tunnel as built until you've actually let go of the mouse. During a couple of my builds I accidentally created a tunnel and was debited, but I hadn't release the mouse. So I backed up and built something else and was still able to obtain the achievement.

What I didn't try was destroying my tunnel and building a different one, so its not clear if the one tunnel rule means only one specific tunnel for the whole game or just one tunnel at any given point in time.

Strategy wise, placement of upgraded stations seems to be important. Since unique symbols appear on both sides of the river, you need the stops on each side of the tunnel to load/unload quickly. (I also didn't get any square stations south of the river, so I also had to move my square passengers across quickly.)

So am I supposed to have only one tunnel in entire game, right. But when I have one tunnel while I am in pause mode and I build second, immediately delete him and un-pause game. Does it works?

[robofish126]

You can earn the achievement even if you build, unbuild, then rebuild your one allowed tunnel. I delayed building the new tunnel until after unpausing and seeing the old vanish though I'm not sure if that was strictly necessary.

However as the above discussion illustrates, recycling the tunnel IS necessary to have a reliable chance at the achievement. You simply delete the tunnel, create a phantom line to empty the isolated station, then delete the phantom line and rebuild the standard tunnel.