Costs of tunnels

[AP]

I wonder whether there is a case for reducing the number of passengers generated by a city hall?

I don't see quite why it needs a 'resident' population at all, it leads to oddities with the smallest villages in particular as has been said. Functioning as an 'attraction' would be much more plausible, like the new pak-gb cathedrals. In an ideal world, it might start as a village green, then evolve into a mediaeval market hall, then later into the neoclassical design we normally see, all with zero residents.

[sdog]

It has a rather sensible effect for the smaller villages by reducing their footprint. A village with 1000 population is far smaller than a square km, if the townhall has no sizeable population it would quickly sprawl to very large areas. Soon making decent city densities/distances impossible as they would quickly grow into each other.

[Isaac Eiland-Hall]

Erm... Let me see if I'm understanding correctly.

If a town hall has 250 people, then:

- A town with 500 people will have half in the town hall, and half in the city.
- A town with 750 people will have twice the sprawl as a town with 500, since the amount outside city hall doubles.

I started up pak64, set townsize to zero, and manually grew the city. Here's two examples:



and



I don't think the effect is noticeable, and makes it harder to internally serve passengers, because you can't transport people from townhall to the same townhall, so you inherently have fewer passengers to transport. :shrug:

[AP]

Indeed - if those 250 people lived in houses, I could bus them between and amongst each other.

[we're drifting off topic, maybe someone friendly can split the thread?]

[dustNbone]

Yeah but a town of 250 people doesn't need any internal transport services at all.  Those people all would all live within sight of each other.

[Isaac Eiland-Hall]

A town of a couple of thousand would also not need any internal transportation, either.

I live in a metro area with around 100,000, and we barely have public transportation - something like six bus routes that generally run every half hour, week days only; with slower service weekend days, no nights.

[omikron]

That's America, I'd say.... :-)

In RL, I think the first bus services start at about 20,000 inhabitants. But in Simutrans, I think having them necessary at about 700 is not too bad.

omikron

[jamespetts]

The problem is that, in Simutrans, the population numbers do not really have any correlation to real population numbers. I hope to fix this one day...

[dustNbone]

In smaller towns in BC, Canada here we have small simple bus services for most places with 5,000 or more people.  Typically a loop type service within the town itself and a few routes that extend into the rural areas surrounding.  However, these aren't for profit services, they are provided as a service by provincial and municipal authorities.  Fares are collected by don't even come near covering costs.  Of course this is also rural BC we're talking about here, not really representative of normal in any way.

As to tunnel costs, I agree that it should cost much more to construct them under most conditions, but it may be difficult to implement with anything like the current system in place.  Tunnels under cities for example, I think would cost alot more to build than a tunnel under a city than through a hill away from population.  Undersea tunnels should be possible, I think at varying levels of maximum depth, deeper available as time passes.  They should be very expensive however, both to build and maintain, especially in the early game when the technology was immature.  I think even 10x current costs wouldn't be unreasonable for many tunnels, along with some more constraints on when and how deep they can be built.

[jamespetts]

Interesting thoughts. A tunnel under a tile that is within the limits of some city can fairly easily be made more expensive to build. However, the complexity increases substantially when one starts to add features such as layers of depth each costing a different amount per tile, and the question becomes how to represent this to a player in a way that makes sense.

Does anyone have any sources on how much more that an under-city tunnel should cost?

[ӔO]

hmm, well, locally, these come to mind:

http://en.wikipedia.org/wiki/Spadina_Expressway
Not underground at all, but it's in a trench. There were plans to extend the rest of the southern portion through tunnels entirely, but it never came to be due to budget constraints.

Gardiner expressway
http://www.canada.com/nationalpost/news/story.html?id=d03892e0-552b-4316-9946-2f0c7146c9ad
C$12 million in maintenance fees
C$758 million to raze
C$1.5 billion to demolish and replace with an underground one
All are estimated, so these number are most likely conservative.

http://en.wikipedia.org/wiki/Toronto_subway_and_RT#Yonge_route
I believe this line is mostly cut and cover, as it's not very deep.


more recently, this line cost just under $1 billion to build
http://en.wikipedia.org/wiki/Sheppard_line#Origins

There is an episode about the london underground from the series "super structures", which doesn't give costs, but does describe difficulties associated with tunneling. http://www.youtube.com/watch?v=7PIdUwfDPzU

[dustNbone]

I was thinking more of having different tunnel types (representing different techniques) with varying depth limits, but only for undersea.  I don't think tunnels get more expensive in deep ground above sea level, but there should be limits/penalites associated with undersea tunneling, on the server map it was way to easy for me to build long tunnels underwater, and probably too early in time for it to be practical.  That said, the Channel Tunnel probably could have been built quite early in the 20th century, maybe even before had the will to do so been there.  I'm not sure what the actual height per level being represented in Simutrans is though, or how the depth of the Channel would translate to that.

Also we recently completed the Canada Line http://en.wikipedia.org/wiki/Canada_Line

About 9km of tunnel, 3km of which was bored under the downtown core.  Then 7.5km elevated and about 1.5km at grade, total cost about $2bn.  That did include compensation for the disruption caused by the cut and cover tunneling along the Cambie corridor, as the line was literally laid under a 6 lane city road the entire way.  I guess it was cheaper than boring all the way, and it did allow the stations to be fairly close to surface level.

[ӔO]

here are a few more.
http://en.wikipedia.org/wiki/St._Clair_Tunnel
$2.7 million in 1890 for a 700m, single line rail tunnel under a river.

http://en.wikipedia.org/wiki/Detroit%E2%80%93Windsor_Tunnel
$25 million in 1930 for a 1 mile two lane road tunnel under a river.

another interesting place to look at might be the New York city subway lines.
http://en.wikipedia.org/wiki/IND_63rd_Street_Line

[sdog]

there's quite a difference between subway tunnels and mountain tunnels. here's a good entrance to modern tunneling.
http://en.wikipedia.org/wiki/New_Austrian_Tunnelling_method

in bored modern tunnels in the alps progress can vary between a few cm a day to 10 m a day, based on rock structure. the time is the main factor determining the construction cost(overruns) of a tunnel.

the NEAT gotthart base tunnel is perhaps one of the most ambitious tunnel projects realized. This highlights the different approaches to different terrain.

They hit rather bad rock, (called in german sugar like dolomite, as it is as hard and grainy as a sugar cube). In general the rock is rather inhomogenous in the important parts to cross of the alps with many faults and layers of very different rock types.

(this was the reason i got a bit into that matter a while ago: http://en.wikipedia.org/wiki/Brenner_Base_Tunnel)

corrosion is also quite different in tunnels compared to surface or shallow tunnels. as waters often have a high load of solved minerals. regular concretes can often not be used.

[el_slapper]

link in french :
http://tunnels.piarc.org/fr/considerations-strategiques/couts.htm

Rough translation of relevant elements :

==>ratios of costs vary from 1 to 5, depending on :
-geologic conditions
-difficulty of access
-wether the tunnel is in urban zone
-length of a tunnel : there is an increased cost for entrance & exit, but also an increase for very long tunnels due to fans & safety
-expected traffic, both in numbers & nature(alowing dangerous goods means safety increased costs)
-tunnel environment(i.e. you may have to protect tree & treehuggers).
-risk management & insurance management
-social & economic conditions of the country : impact up to 20%


==>in average, something built underground costs 10 times more than the same infrastructure built outside, far from an urban zone, & not counting possible bridges.

depending on its complexity, "direct works" costs between 70% & 85% of the tunnel. The rest is balanced 50/50 between equipment & miscellaneous.

==>"exploitation costs"(maintenance, big repairs, salaries, energy, overhead) represent between 5.5% & 8% of the total cost of the tunnel - for a 30 years exploitation. The easier the tunnel is to build, the greater those costs are.

==>"upgrade costs" are simply too complex & variable to give relevant data.



it also has elements about financing, though to translate & irrelevant to simutrans(I think). Other chapters deal with tunnel micro-management, safety & environment.

EDIT : mistranslation of "génie civil".

[jamespetts]

Thank you all for the lovely information - very helpful!

[wlindley]

Is there a way to restrict certain classes of tunnels to a maximum length (distance from tunnel mouth), or to make a tunnel-mouth tile (the entry or exit) cost much more?

[jamespetts]

I think that a maximum length would be very difficult to calculate (maximum distance from which tunnel mouth? What if the tunnel diverges? Etc.), although it should be possible in principle to charge more for the tunnel entrance; the questions are, though, (1) how does one represent this to a player clearly when there is a "cost per km" in the menu tooltip; and (2) is this really necessary for tunnels to balance adequately?

[sdog]

I don't think it would be necessary. The cost of building tunnels varies so greatly, we can not model it in detail at all. The reasonable approach is to give it a good overal value, reflecting averaging over a large number of tunnels.

You could make, with way restrictions, another tunnel type for the tube, that is considerably cheaper to maintain, as subways are never very deep underground. Thus they are only bored in good rock and built with cut and cover methods in adverse rock formations.

St Gottardo:
15km tunnel 227 Mio. SFr. in 1880

30t normal gauge locomotive, GB Ed 2/2
30kN pull
51000 SFr in 1874 or 1883

http://de.wikipedia.org/wiki/GB_Ed_2/2


google image search brought this image of the loco

[jamespetts]

Ahh, urban metro tunnels are a different consideration again: we can use the way constraints feature for that (indeed, that was one of the reasons behind its invention), so that is straightforward. We do, I think, need to make undersea tunnels cost more, but that is straightforward and should be easily understood by the player. I think that you are right, however, that we do not need to (and cannot sensibly) simulate differential tunnelling costs in any more detail than this.

The real question a definitive answer to which has so far evaded me is how do we model cut and cover tunnels, which were very important in the earlier days of the London Underground? Two possibilities present themselves.

(1) One could model them literally by the use of the artificial slopes tool and elevated roads. This has the advantage that it can be implemented with current code, but the disadvantage that one will often want to build a double track line, which is not possible under a single road, and one cannot build this sort of "tunnel" and then let any buildings grow on the top.

(2) Alternatively, one could introduce a cut and cover type of tunnel (or flag), and have a tunnel type that can only be built 1 or 2 tiles (perhaps) beneath the surface. They could then be defined as having a lower cost in the pakset. This would have the disadvantage that it would not easily be able to check what buildings are on top of it, and so could not prevent players treating it as a mined tunnel in some respects by digging underneath a factory, town hall, attraction, etc.

I should be interested in thoughts on this issue.

[omikron]

That's somehow related to this thread: http://forum.simutrans.com/index.php?topic=9225.msg86335#msg86335

Maybe it would be possible to build buildings and/or ways which function like a terraformer?

omikron

[wlindley]

Support the "tube/subway" waytype tunnels, and undersea tunnels.


For regular tunnels -- Until fancier algorithms are in place, would a range of weights+speeds suffice, with a somewhat logarithmic escalation of prices as time advances and speeds increase, perhaps using a variation of fabio's new pak128 tunnel graphics? -- see: pak128 Tracks replacement project

[jamespetts]

The real problem with weight/speed limits is that these are tied to the track, not the tunnel itself. Currently, there is no good way of separating the track and the tunnel in Simutrans, which causes problems.

[omikron]

What do you mean? there are tracks in tunnels, only they have to use the tunnel tool. As far as I understand fabio's project, he wants to introduce different tunnels for different speeds (and weights). That way, the tunnel cost coudl also be differentiated according to weight and speed.

[jamespetts]

Ahh, but the problem is that, in real life, tracks are not fixed to tunnels. In reality, if one builds a tunnel in 1865, and puts old wrought iron track in it that can only take a weight of, say, 75t before it buckles, one can easily replace the track in 1890 with steel track that can cope with a much higher weight at the same (or very slightly higher) cost than replacing wrought iron track with steel track not in a tunnel.

However, in Simutrans, to replace a tunnel with a weight limit of 75t with one with a weight limit of 150t costs the same as building the new tunnel with the weight of 150t. This is a real balance problem.

[AP]

Here's a related thought.  Should there be a way restriction on tunnels over a certain length? Because there are exhaust issues with steam locomotives (and also diesel) in tunnels, so longer tunnels ought really to be electric-only.
Might open a can of worms though...

[jamespetts]

That is a very complicated issue indeed: steam trains did, in fact, use very long tunnels (and in the 1863-1905 period, much of the sub-surface part of the London Underground was steam operated). The London Underground steam locomotives, that called at in-tunnel stations had to be fitted with condensing equipment, but ordinary steam locomotives using, say, the Severn Tunnel did not.

[ӔO]

even today, there are diesel electrics that are specifically designed for use in mountain ranges with lots of tunnels.

I wouldn't worry too much about the replacement costs of tunnels, because the old ones are usually abandoned and plugged up when they become inadequate or they never get upgraded and are used with specific vehicles that have very tight dimensions to not exceed the limits of the tunnel, like the london underground.

It would possibly be easier to simulate this with a cheapening of costs for newer tunnels. But in the end I think they would be priced higher due to inflation.

[jamespetts]

Hmm - UK railways don't tend to abandon their tunnels and build new ones except very rarely (the Woodhead tunnel being a good example).

[ӔO]

this is one reason why UK can't use double decker cars

I think hajo was talking about the piston effect in another thread?
the 2009 stock has rolled sides, which helps with the aerodynamics quite a lot in tunnels and indeed it has better performance than the 1967 stock it replaced. Although this is probably also in part to better motors.

[sdog]

We do, I think, need to make undersea tunnels cost more

we already have that in effect, you have to dig down first then go below the deepest spot. this increase the length of a tunnel considerably, whey also keeping an acceptable incline.

If you really want an improvement, require that there is at least one empty square below a sea tile before  tunnel comes. in other words, prohibit tunnels in a square directly below water. players have to go deeper in their under sea tunnels.

The real question a definitive answer to which has so far evaded me is how do we model cut and cover tunnels, which were very important in the earlier days of the London Underground? Two possibilities present themselves.


[...]

Implementation of a new way is enough here to cover ut and cover and bored tunnels. in effect both do the same, but the player shouldn't bothered with a very tedious way to build those.
The difference in building costs should not be too much of an issue either: When one has good hard rock boring would usually be cheaper, while in soft sediments or silts cut-and-over is. Just asume the civil engineers you employ in game just chose the cheaper one. Thus use a reasonable average based on what the underground in london actually cost in relation to surface rail.

[jamespetts]

I don't think that this differential is sufficient to account for the greatly increased cost of undersea tunnels, however.

[sdog]

i don't see where this massive cost increase in undersea tunnels else would come from. The channel tunnel had costs of same magnitude as the gotthard base tunnel. A factor of two or three wouldn't change a lot either. The Seikan tunnel was in comparison dirt cheap.

If the ground is suitable it shouldn't matter too much if the pressure is that high due to a mountain on top or the sea. Managing water is an issue in both cases. If the ground is unsuitable, a tunnel couldn't be built anyways. This last sentence comes back to what i wrote before, i hope i don't bore you whith it, we do not model most of the factors relevant for the feasibility and cost of a tunnel. The cost of tunnels depend mostly on such factors (with order of magnitude cost difference) but we discuss cost increases based on minor differences. If implemented it would only increase complexity without improving the simulation. In fact it would cause the simulation to be less accurate.


ps.: your use of the word differential is a confusing as you do not mean d/dx, what i would expect in an engineering or natural science context.

[jamespetts]

Ahh, hmm, I see the point. Perhaps it is unnecessary, then, to have a different cost of building undersea tunnels. I shall have to consider your earlier proposal further, and think about how easy that it might be to implement.

[ӔO]

If you don't mind increasing menu bar clutter, I would go with something like dividing the two.
Underwater Tunnel and Land Tunnel.
Add such a value like max depth below sea water, similar to bridge max heights.
A tunnel meant for crossing a river can have something like max_depth=-1
A tunnel meant for crossing the ocean can have something like max_depth=-7
A tunnel meant for mountains can just use max_depth=0

for cut and cover, the method of cutting a trench, then paving over it with elevated road should do. The only caveat with this is how it's impossible to do over cities that are sitting at sea level 1, where trenches end up being filled with water.