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Costs of tunnels

Started by AP, February 05, 2012, 05:46:39 PM

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AP

All good points.
Quote from: sdog on February 05, 2012, 05:41:13 PM
There should be two massive cost drops in tunnel building, introduction of dynamite (uk patent 7 may 1867) and recent prefabricated tubbings and automated drill machines.
Sounds good. Maybe we need different types of tunnels, like track, becoming available.

I recall seeing someone improving the entrance portal graphics (the current ones have a roof rather than a cutting) - presumably that's a pak issue though.

Mod note - split from the balancing discussion

jamespetts

That's very interesting. Unfortunately, I suspect that it would be extremely difficult for the game to calculate which tiles are under flat land and which under steep mountains. As to tunnelling costs reducing - are they not possibly offset by increased labour costs? Or is a million pounds in the 1870s/1880s for a 4 mile tunnel (the Severn) greater proportionately than tunnels cost to build now, in real terms?
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omikron

The 5,3 km long Gravhalstunnelen in on the Bergen Railway in Norway cost only 3 million Norwegian kroner to build in 1906. That would be about 150,000 GBP at the time. Just to show what granite underground can help....

omikron

jamespetts

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sdog

"As to tunnelling costs reducing - are they not possibly offset by increased labour costs?"

likely not, but it won't be possible to see, tunnels were hardly dug in anything but the best geological situations, this has changed. The Thames tunnel of the 19th century is an example for exceptions from this.

There was lower labour cost, but higher capital cost, it was a high risk operation, many tunnels caved in with complete loss of investment.

omikron

Well, another Norwegian rail tunnel, built in 1997 was 14,5 km long and cost 13 Billion Norwegian kroner (= 1,5 Billion GBP), because it was built under a lake, which leaked into the tunnel and made the building costs explode....

I don't think any general rule can actually be defined. MAybe one could make a price range, with the actual costs being randomly assigned?

omikron

sdog

possibly bancrupting your company?

to quote another game related to dig underground: "fun!"

jamespetts

Hmm, I don't think that making the costs of tunnelling random is a good idea.
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omikron

I didn't mean random, but a random price within a range, so that (example): 1 tile tunnel costs 5-15, with 50% probability that the costs stay in the range between 9 and 11, 35 % costing 7-8 or12-13 and 15 % 5-6 or 14-15. Do you get my idea?

omikron

jamespetts

Yes, I understood that it was within a range, but I think that there are big problems with having even constrained random costings: this would be very confusing for players.
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omikron

OK. I thought experimental was meant for people who are not getting easily confused :-)

And building a tunnel is always risky, so why not?

omikron

AP

Quote from: omikron on February 05, 2012, 08:54:57 PMOK. I thought experimental was meant for people who are not getting easily confused :-)
He has a point!

I quite like the idea of random-within-a-range. It would mean that short tunnels had a small variance in price possible, long tunnels a much larger one. It would mean small companies would only prudently undertake small scale works, which is realistic, whereas large companies could commit to larger works. Real companies can have/have had financial difficulties due to works costing more than predicted, factoring risk into the game for large structures would encourage "responsible" gameplay, perhaps?

jamespetts

I think that even people who are not easily confused would be confused by random costs! It would make no sense to have tunnels and tunnels alone as the things were subject to cost uncertainty: that would be arbitrary. In reality, any sort of project can cost more than anticipated. For this to make any sense, there would have to be a whole system where the cost of projects was uncertain; that would be a large undertaking, and is not currently a priority.
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sdog

if it's not completely getting out of hand, a rough estimate of the building cost often is not so bad today. That's getting far out of the scope of the simulation i think. One has to live with the construction cost of tunnels not being very well simulated in the game, a straight cost increase might be more than enough.

If you really want to do something James, you could make a kind of restricted tunnel, similar to what we had before ctrl-click tunneling and underground mode. So it only could be built straight. Perhaps even build a lenght restriction.

With way restrictions you could still allow tube tunnels to be built unrestrictedly. (most likely they were channeld and covered anyway?) At some point in time large tunnels would also loose the restrictions.

If one really would get into the matter, a geological map could be generated at start of the map. The height structure is then based on this geological structure, drainage decided, major rivers laid, terrain eroded and basins filled up with silt. Based on this restrictions on tunnel building and cost calculations could be done. i doubt it would be worth the whole mess.

wlindley

How about making the cost per unit of tunnel inversely proportional to its altitude?  Tunnels at -1 (under sea level)) could cost much more than at 0 or 1, and progressively less as you rise. 

AP

Would that take into accound mapsettings, e.g. I often play with sea level at -6 or-7, to get more land and less ocean.

jamespetts

It would be possible to make cost relative to sea level, certainly, but the issue is: does tunnelling actually work like this? Does tunnelling on a high plateau really cost that much less than tunnelling on a low plateau?
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ӔO

#17
tunnels cost more, or are impossible with technology at the time, on certain sub-surfaces.
I believe that the Chicago L is mostly elevated, because the ground was unsuitable for tunneling.

You might want to look on the wiki page of tunnels, particularly, 3.6, 3.11 and 3.12

There was also a documentary from discovery on the channel tunnel that might be interesting to look at. I believe it was from the series Mega Structures (Super Structures).
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el_slapper

Hi everyone, my first post over there. Though a long-time player & lurker.

That idea of variability in building(here, tunnels) costs is really good in terms of realism. However, I fear it's a can of worms waiting to be opened.

Anything built is dependant on local constraints. Roads in the desert or in the jungle tend to cost more to maintain. Randomness still exists in building projects, with more variability for bigger projects. Mainly because bigger projects are rare. If you build 10,000 times the same house, the same road, the same railroad crossing, costs are well known & mastered. But for huge projects, well, you are basically doing a new design each time. And, therefore, there are many unknowns. I'd say that due to the tricky & changing state of the soil, tunnels are especially prone to that kind of effects. But if you begin with tunnels, you'll have to code - and balance - a biiiig number of variations.

I don't say it shouldn't be done; just, think strong before beginning. A proper balance of variable building costs can be an absolute pain to achieve.

sdog

hi el_slapper, welcome to the forum, as a participant.

I'm not so sure if a height level dependency of tunnel building costs is sensible at all. it seems rather arbitrary to me.

omikron

If you want to make tunnel costs less linear and more like reality, then some arbitrqariness cannot be avoided. As said above by someone, every major tunnel project (and to a lesser extent bridge, track and road project) is hugely dependent on a variety of factors which differ hugely from case to case, so the same tunnel length in two different contexts may cost up to ten times the same amount, if not more.

My take on this would be to make random costs within a range - the range need not be very large, but it makes things a bit less certain. How many of you calculate the cost of a tunnel manually before building it in simutrans anyway? If you do it with the key combination (which I forgot), then the result being a range would not distrube you very much, would it?

I'm simply asking, but I will give up if there is massive opposition...

omikron

AP

Maybe it is a feature which could be introduced later, once the game is more well-balanced and stable. That would make James' life rather easier I'm sure!

sdog

it would be a bit difficult to have a random value for the whole tunnel.

If you do it straight forward on a per tunnel tile base, this would only matter for the shortest tunnels. When building longer tunnels you would rather quickly get close to the expectation value.

A more general remark, one can be quite a bit arbitrary, in finding good and useable approximations. However if it is very uninformed, or based on a very rough model, as we have here it is better to sticky to simple models. Above Omikron described how different the costs for a simple tunnel in hard rock are compared to james' examples in difficult terrain. We flatten that much larger effect, but should introduce a much weaker effect addressing the uncertainty of a tunnel project? In such a case, better get a geological model for map generation. (which is entirely possible to do, has quite some benefits for industrie placement, just quite a bit overkill)


In simulations one has to look what effects are important, and what less so. There's quite a lot much more urgent in the economic model. Building tunnels is not a very important aspect of the game.

AP

Quote from: sdog on February 06, 2012, 09:10:29 PMThere's quite a lot much more urgent in the economic model. Building tunnels is not a very important aspect of the game.
I agree with the first statement, disagree with the second.

There are a lot more important elements needing balancing.

However, as the recent online game showed, later in the game players are very happy to build significant tunnels (under whole towns) where in real life this is unlikely to have occured. That this is done suggests that there is no adversity to the idea of building miles of tunnels - which should be considered a considerable undertaking done only when there is no reasonable alternative.

sdog

Making it terribly expensive should do the trick.

The rest is a kind of players code of conduct not to play too abusively. Rich players can terraform the whole map, delete towns and build a railway in the sky with viaducts. As long as there's an abundance of cash there's no way to stop. Trying to build artificial restrictions often just causes a financial broker effect. Completely reasonable bank managers invested in terrribly unreasonable ways, just because they found a loophole in the strict network of regulations. The legislative and executive reacted, closed the loopholes and the game really started.

jamespetts

El_slapper,

welcome to the forums! You make a very sensible point, in that variable building costs are a large and very difficult area, not ready for consideration until such time as we are rather more advanced in the more basic echelons of game balance, which, if executed correctly, would hopefully prevent players from having such enormous amounts of money that they can afford to build vast tracts of railway network underground just because to do so is more convenient.

The priority for this year's development is balancing, and making tunnels expensive enough is part of that work. Thank you all for your input into this topic!
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ӔO

Quote from: AP on February 06, 2012, 09:52:50 PM
I agree with the first statement, disagree with the second.

There are a lot more important elements needing balancing.

However, as the recent online game showed, later in the game players are very happy to build significant tunnels (under whole towns) where in real life this is unlikely to have occured. That this is done suggests that there is no adversity to the idea of building miles of tunnels - which should be considered a considerable undertaking done only when there is no reasonable alternative.

part of the problem is in how you have to connect the city halls to get any passenger flow, but the cost of demolishing buildings to build your station next to the city hall is astronomical. And the horse carriages are very inadequate to making this connection. Not only that, but cities can't grow beyond double tracks without some luck and major stations require a lot of room. Even the larger cities would have problems if you try and fit 2 or 3 major stations from different players.

Around the 1850's the tunnel upkeep was far beyond sustainable, but by 1880's, the profits from expresses allowed a lot of the upkeep to be negated. It's not so much the expense, but the upkeep that held back tunnels earlier in the game.
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merry

hi,

re: tunnels & underground stations, and indeed urban railways, the national preferences & circumstances seem to have heavily informed choices IRL.
Example:
(1) In the UK, we just don't do large underground stations. Never really have. But we seem to be very happy to put railways on viaducts through our cities. And indeed, many central city stations are largely on viaduct (or in cutting).
(2) Spain: Barcelona & Madrid both have large central stations wholly or partly underground. Barcelona in particular - it's huge! But I didn't see many viaducts even thought the approaches are often from higher ground, indeed many approaches were underground.
(3) Paris (also Holland & Belgium I think) have both put suburban stations wholly under the associated mainline station, to allow expansion of capacity without enlarged footprint, and avoiding complex approach trackwork.

i would suggest trying to encourage one particular approach by financial means is not necessary nor appropriate, provided it is overall balanced...ground level city track needs to buy costly property, elevated track needs expensive viaducts, and it's not cheap to tunnel. But all are valid solutions and frankly all will be done - to large sizes - if the money is there.

re: variable building costs, even I think it's is a step too far, and will make the game pretty unplayable to all but the most dedicated - unless you also implement gradual (timed, not instant) construction and gradual cost billing, allowing a player to abandon a works that is turning out too costly. Set a budget, report back on progress, etc. A bit micro-management oriented for many players.

re: terraforming, I think the costs are already high, and limit the poor player's ability to do works in their early build. But as cash builds up, the ability to build smoother routes improves. This is normal. A rich player will be able to do anything permitted by the civil authorities.

whether all these are desirable situations is questionable, I don't do network play (way too intermittent & short time available) so can't comment there.

merry.

AP

Quote from: AEO on February 07, 2012, 01:16:25 AMpart of the problem is in how you have to connect the city halls to get any passenger flow
Since when? Can someone confirm? I thought the city halls were just an interface...

ӔO

Quote from: AP on February 07, 2012, 07:48:11 PM
Since when? Can someone confirm? I thought the city halls were just an interface...

this was always the case.
for any significant flow of traffic to be achieved, the city halls must be connected. Having the station within the city boundary is not enough.
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AP

Well we learn something every day!  ;D

sdog

the first 250 (?) inhabitants live in the city hall. thats also the reason why very small villages get created only with cityhalls but no residential buildings.

jamespetts

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

this would also make hamlets to sprawl. (just imagine city hall as a more densely built village core, afterall it's on an area of a quarter square kilometre! (4 in standard)

You could increase building population and reduce passenger factor. This would tone down the effect of the town-hall. It is however, i think, not undesirable. It is the most likely place one would travel to and from in a city. in a way you could see it as the place where all the folks from sourounding farmsteads go to pick up their transport.

el_slapper

Quote from: merry on February 07, 2012, 12:53:28 PM(3) Paris (also Holland & Belgium I think) have both put suburban stations wholly under the associated mainline station, to allow expansion of capacity without enlarged footprint, and avoiding complex approach trackwork.

+1, though this is mainly true for Paris. Other french towns mostly have surface elements(with a few exceptions).

I guess the sheer size of Paris did push towards different solutions. There's another point : before the 1936 nationalization, there was 3 private companies building subways & fighting each other. It has several consequences, still today : an absolutely excellent subway coverage, but, at the same time, a , hum, subpar optimization of the interconnexions. BIG underground stations have been built later, once everything went state-owned, in an effort to reduce the chaos of the network. I'd say that effort was partly successful.

Another consequence is that Paris's underground is an absolute Swiss Cheese, and the relatively new RER E line is built one level under other lines. Stairs down are endless to get there. In St-Lazare(one of the stations in Paris intra-muros)I need nearly 10 minutes of walk from the RER E to my surface train(bringing me back home in my suburb). But I'm clueless on how to translate those difficulties in terms of gameplay.

AP

Quote from: jamespetts on February 08, 2012, 12:22:26 AM
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...
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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?
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ӔO

#45
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
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dustNbone

#46
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
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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!
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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?
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sdog

#53
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.
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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.
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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.
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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.
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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.
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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).
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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.
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sdog

#65
QuoteWe 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.


QuoteThe 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.
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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.
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ӔO

#69
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.
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greenling

Good Day
excuse Me.
The Idea too Limiting the builddepth of tunnels in mountains,under ocean and river it´s a bad idea.
better it to leaving a limit away.
(That be save freetime to find another bugs.)
Thank you
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