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Offline neroden

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Re: Ideas on range management
« Reply #35 on: June 10, 2013, 08:57:58 PM »
Range was particularly important for steam trains, as Valdki suggests, as well as for aircraft. It is of more limited importance to other forms of transport, but, even so, there are diesel locomotives on railways with extended fuel tanks compared to others in the same class especially for longer trips, so this not an issue confined entirely to steam and aircraft. It is probably particularly relevant to steamships, too, however, as well as long distance road transport (I don't think that a 'bus from 1950 could travel 500km without stopping, for example). As for going slowly - I don't think that that makes any sense: a steam locomotive cannot move at all if it is out of water, so it should not set off unless it knows that the next stop is within range.

I don't think that it's worth it to implement the entire refueling network concept at this time.  There are far too many other things to fix first.

But it's an interesting idea.  I think for trains and road vehicles, it should be mandatory to set scheduled stops at refueling points, even if you aren't picking up or dropping off anyone, so that simplifies the problem a lot.  This would reduce the problem to the following: refuse to launch unless you can get to the next stop within your fuel supply. 

If the player is silly enough to set up a bunch of stops without fuel supply, I think it's OK for the trains/planes/etc. to get stuck at those stops, since the player should be able to upgrade them with fuel supplies.  They can also teleport home if necessary.

An important point, however, is that vehicles don't use a constant amount of fuel in any way, shape, or form.  Having more fuel-efficient locomotives was a critical part of the history of trains, and the same was true for road vehicles, airplanes, and ships.  Also, much more fuel is generally consumed going uphill than going downhill.

So this makes the whole thing much more complicated.  It is very hard to estimate in advance whether you have enough fuel to get to the next stop.  We could probably make an estimate, but not a *reliable* estimate.  Just as we can estimate journey times, but when we actually run the convoys, the journey times are somewhat different.  And just as our estimates of haulable weight and top speed are often a little off from what really happens (though I'd like to fix that).

If we are willing to put some effort onto the player, we can simply allow the trains & planes to start, and if they run out of fuel, warn the player and teleport them back to the depot.  We can give a warning in advance if our estimate says that we're likely to run out of fuel.

One thing I will say:  I don't think "range" is at all a suitable method of implementation, due to the different fuel usage profiles of different vehicles.  If you're going to do this, go ahead and actually implement fuel, properly: burn it as the running costs are incurred.

Offline jamespetts gb

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Re: Ideas on range management
« Reply #36 on: June 10, 2013, 10:31:12 PM »
Interesting discussion. I definitely agree that this is a low priority issue, so need not be considered conclusively at this time. It is interesting to ponder these things for the future, though.

One more thing to consider theoretically: are there any other significant limits on range apart from fuel that impact on the types of transport simulated in Simutrans?

Offline Michael Hauber

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Re: Ideas on range management
« Reply #37 on: June 12, 2013, 02:12:52 AM »
Crew (i.e. person driving the vehicle) constraints are an issue in many rail (and presumably truck) freight operations in Australia.  Distances run into 1000s of kilometres, which means more than the 10-12 hours that a single driver (possibly with backup driver) can operate.  Crew depot locations need to be placed so that a train can change drivers when the shift is over, and sometimes fun stuff happens like crew being sent to the middle of nowhere by taxi, or crew changing from one train to another train going the opposite direction in an attempt to get maximum possible use of the crew if there is a shortage, without going over legal shift limits.

This really only applies to freight moving distances longer than I've seen so far in Simutrans (assuming 250m/tile), although if I remember right a train can get further on one tank of fuel than it can on one driver(pair of drivers).

Offline neroden

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Re: Ideas on range management
« Reply #38 on: June 12, 2013, 09:15:51 PM »
Crew (i.e. person driving the vehicle) constraints are an issue in many rail (and presumably truck) freight operations in Australia.  Distances run into 1000s of kilometres, which means more than the 10-12 hours that a single driver (possibly with backup driver) can operate.  Crew depot locations need to be placed so that a train can change drivers when the shift is over, and sometimes fun stuff happens like crew being sent to the middle of nowhere by taxi,
This is what is done in the US in these situations too.  Crew change points are placed whereever the crew is expected to "run out of hours" (in the US there is a strict legal maximum) and the crew are forced to move their homes to near the crew change points.  Which sometimes have no stations, just walking up off of ballast.  Given that, I think it's not worth implementing crew change points.