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Offline Moe Ron

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Question about DLR units
« on: August 17, 2014, 11:48:00 PM »
Tell me, why is it that the DLR EMUs can't use the modern tube tunnel? After looking at some videos, it seems that they fully utilise it at bank en route to the east.

http://youtu.be/YjG_gUs6xFQ?t=7m17s
http://youtu.be/DXL7u59MwPY
http://youtu.be/l8gvhqHq4qs

Offline kierongreen

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Re: Question about DLR units
« Reply #1 on: August 18, 2014, 12:25:29 AM »
While the DLR tunnels in those videos look similar to tube tunnels they are actually much bigger. Notice how when people walk onto a DLR train there is plenty of headroom - on tube trains there is hardly any.

Offline DrSuperGood

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Re: Question about DLR units
« Reply #2 on: August 18, 2014, 10:36:29 PM »
The problem I think is that there is a distinct lack of tunnel variety in this pakset, at least in the current release version used by the online server. End game you only have 2-3 tunnel types, of which the fastest is an insignificant 140 km/h (any slower and taking a car would be quicker!).

The channel tunnel is 160 km/h but that is hardly a state of the art railway tunnel (it is quite old now).
It would be nice if there were some high speed tunnels (almost rail speed? if not rail speed?) and some more cost efficient low speed tunnels (do undergrounds really cost so much in maintenance?). Tunnels speed limits for railways are not easily discovered knowledge unless you know what you are looking for.

On an unrelated note power tunnels should probably have a huge maintenance cost reduction. I do not think their multiple fold maintenance cost over standard transmission lines is that accurate and certainly is not good for game play (we want them underground, not above ground as that takes huge amounts of land).


Offline kierongreen

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Re: Question about DLR units
« Reply #3 on: August 18, 2014, 11:28:27 PM »
Standard has 350km/h tunnels which reflect real life speeds on HS1 - I don't know about Experimental. The Channel Tunnel is a few years old but there are plenty of tunnels faster than that in the UK. How would cost efficient tunnels be balanced? People would just use them in preference to surface ways which removes challenge from the game. This argument applies even more so to power lines. Underground maintenance does cost a lot more than work on the surface.

Offline Junna

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Re: Question about DLR units
« Reply #4 on: August 19, 2014, 06:40:10 AM »
Part of the reason the Channel tunnel speed limit is that it is a very long tunnel. Shorter tunnels often have higher speed limits. I assume that this lowered speed limit was introduced because very long tunnels would otherwise have excessive speed. The other tunnel, as I recall, is 120km/h, as per the Severn Tunnel speed limit. If there was such a thing as limit of length for tunnels it might be good to have some higher limit tunnels...

That aside, the conventional tunnels sort of need underground graphics, but I suppose no one has bothered with that yet.

Offline prissi

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Re: Question about DLR units
« Reply #5 on: August 19, 2014, 09:00:52 PM »
Putting high power transmission lines underground is 10-6x times more expensive to built and about 3-5x more expensive to maintain, because you need active oil cooling instead just lines hanging from pylons in fresh air ...

Offline DrSuperGood

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Re: Question about DLR units
« Reply #6 on: August 20, 2014, 02:22:36 PM »
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Putting high power transmission lines underground is 10-6x times more expensive to built and about 3-5x more expensive to maintain, because you need active oil cooling instead just lines hanging from pylons in fresh air ...
EXACTLY! Not 100 times more expensive to maintain like in standard pak64, pak128 and experimental pak128 Britain. In Pak64 standard it is more expensive to maintain a power tunnel per tile than it is to have a road tunnel and tram track or a high speed road tunnel.

Also I would imagine active oil cooling depends on the line load (they can probably run hotter underground since the problem with above ground lines is line sag and snapping when running hot, a problem I do not think affects underground cables). However even still paying 6-10 maintenance per tile of power tunnel in pak64 standard would be a huge improvement over 200 per tile of power tunnel which it is now (standard road tunnel is half that at 100 per tile). This also affects Experimental Pak128 Britain where power tunnels also have a huge unrealistic maintenance cost over standard power lines.

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Part of the reason the Channel tunnel speed limit is that it is a very long tunnel.
Also it was designed/built before highspeed engineering really started to take off. High speed tunnels have to be designed slightly differently from standard tunnels including special exits to avoid defining nearby people with a shockwave. Obviously this would reflect on their cost to build and maintenance but the fact is I am sure there are rail tunnels with a speed limit higher than the low speed ones available currently. Without such tunnels designing high speed passenger networks becomes very difficult since it cannot use underground at any time other than arrival/departure to a station (where it is slow anyway).

Offline kierongreen

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Re: Question about DLR units
« Reply #7 on: August 20, 2014, 04:10:01 PM »
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Also it was designed/built before highspeed engineering really started to take off. High speed tunnels have to be designed slightly differently from standard tunnels including special exits to avoid defining nearby people with a shockwave. Obviously this would reflect on their cost to build and maintenance but the fact is I am sure there are rail tunnels with a speed limit higher than the low speed ones available currently. Without such tunnels designing high speed passenger networks becomes very difficult since it cannot use underground at any time other than arrival/departure to a station (where it is slow anyway).
The Channel Tunnel was built from 1987-1993 at which time high speed engineering was around. The mix of trains using the tunnel is the main limiting factor when it comes to speed - as well as Eurostars (TGV) you have passenger and freight shuttles which have a much lower maximum speed.

I reiterate - there are high speed tunnels available in Standard Pak128.Britain, and the large maintenance costs are there to balance the pakset otherwise people would have an overwhelming tendency to build everything underground.

Offline Sarlock

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Re: Question about DLR units
« Reply #8 on: August 20, 2014, 04:29:21 PM »
Pakset balancing is a major point here.  Regardless of whether something exists in reality or not, it is whether it encourages the desired economic behaviour in the pakset that is important (especially in a multi-player situation).  The limitation in high speed tunnels in pak128.Britain encourages the player to develop above ground high speed rail lines... otherwise the player would opt to drop everything below ground as it's much easier to develop an efficient network without obstacles.

The power lines are less of an issue as it's a small part of the game.

Offline DrSuperGood

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Re: Question about DLR units
« Reply #9 on: August 20, 2014, 05:53:45 PM »
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I reiterate - there are high speed tunnels available in Standard Pak128.Britain, and the large maintenance costs are there to balance the pakset otherwise people would have an overwhelming tendency to build everything underground.
And building underground is bad because? I mean seeing how a double track is 250 meters wide and trains can be nearly 8 KM long to haul only a few thousand tons of cargo... Unless you allow building underground as an alternative people will just pave the maps with rails to be able to supply industry and passenger needs.  As it is the main advantage of water transport is virtually limitless transport bandwidth. (1 tile wide can move several hundred thousand tonns a month in both directions unlike rail). I would say encouraging tunnels is a good compromise.

Also power tunnels should mostly be underground, this is how all power is supplied in cities as there is no room for huge pylons. As it is people complain in servers due to power lines being major hazards for fast tracks.

Offline kierongreen

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Re: Question about DLR units
« Reply #10 on: August 20, 2014, 11:06:12 PM »
Very few power lines to large industries are underground - small scale low voltage distribution maybe but major links are almost always above ground. Equally most of the time it's only intensively operated metro networks that are underground - most railways run on the surface.

Offline Sarlock

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Re: Question about DLR units
« Reply #11 on: August 21, 2014, 06:07:32 AM »
It boils down to pakset preference, ultimately.  I personally prefer encouraging mostly above ground construction, it makes the game more interesting.

Kieron is correct: high voltage lines are very rarely underground (it's very expensive).  Lower voltage lines are underground in many urban areas, but they still come from above ground high voltage lines at transformers.  The same occurs in Simutrans-Experimental: the city provides power to the urban areas underground but receives its main power feed from player-provided (mostly above ground) sources.

Offline DrSuperGood

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Re: Question about DLR units
« Reply #12 on: August 21, 2014, 03:24:45 PM »
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Very few power lines to large industries are underground - small scale low voltage distribution maybe but major links are almost always above ground.
The proposed UK to Scandinavia power lines are undersea cables. Although not underground, they are still not above ground and designed for transferring some serious amounts of power.

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because you need active oil cooling instead just lines hanging from pylons in fresh air ...
You do not need active oil cooling and as far as I can tell no such cables are commonly sold. That said temperature is a major limiting factor with cable length due to the thermal resistance of ground. Even still transferring megawatts of power underground is easy in theory. The actual problem comes from capacitance of long lines underground which is hard for conventional AC transmission to cope with (they are usually limited to stretches of 20 km odd at most) however this is solved by DC power transmission which is what is being employed for the off shore wind farms.

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Equally most of the time it's only intensively operated metro networks that are underground - most railways run on the surface.
Most railways are not 250 meters wide for a double track and most trains are not 375-8000 meters long. A compromise is required.

Power lines also do not have a 125 meter wide footprint and some houses can exist under them and you can even have diagonal roads under them. This is not the case in Simutrans and again a major reason why using power tunnels needs to be encouraged since power lines are a major construction hazard when you do not own them.

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high voltage lines are very rarely underground (it's very expensive).
4 times more expensive to build, 12 times in cities but that is due to non-simulated reasons such as disruption. The main reason they are not commonly used is the capacitance and fixed maximum load ratings. You cannot raise the ratting of a cable easily but you can do so to a line. Classic AC networks can only use them for limited distances (20 km odd) due to the reactive power they produce. However in this day and age this is no longer a problem as DC transmission can be used (no reactive power) or inverse reactive loads can be placed to counteract the problem.

They have less physical resistance than lines due to the thicker conductor used. In DC operation it is completely viable to have high voltage cables of any length.


Offline kierongreen

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Re: Question about DLR units
« Reply #13 on: August 21, 2014, 08:57:58 PM »
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The proposed UK to Scandinavia power lines are undersea cables. Although not underground, they are still not above ground and designed for transferring some serious amounts of power.
Undersea power cables are very expensive! They also aren't actually part of the grid they are links between different grids.

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They have less physical resistance than lines due to the thicker conductor used. In DC operation it is completely viable to have high voltage cables of any length.
Indeed - however the conversion from AC to DC and back to AC again isn't completely lossless, and the equipment used is also quite expensive.