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Buses can only go 4km/h uphill?

Started by Sholong, August 07, 2011, 01:30:13 PM

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Sholong

I had played simutrans experimental 9.12 with the newest pak128 Britain for a week. I am now playing the demo map provided by the pak(the map that automatically being loaded when the game is loaded), however, when I try to set up bus routes through some urban area which are having steep roads, seems that all bus currently available in 1945 can only run on these slope for 4km/h only(I have tried the Leyland Cub, AEC Q4, AEC Regal, AEC Standard STL and the Guy Arab) which greatly affect the normal operation of the bus routes. Is this a problem or is it just a real-life reflecting setting?


jamespetts

Thank you for the report, and welcome to the forums! Whilst 'buses should slow down when going uphill, 4km/h is far too slow. I shall have to look into this issue further when I get a chance. Thank you again for the report!
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jamespetts

I am having trouble reproducing this, I'm afraid. Have you changed any of your simuconf.tab settings from the default?
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ӔO

james, try it with a 90 degree bend at the base, which will scrub off a lot of speed entering the hill. A hill with 3 climbs, like pictured, will finish the job.

IMO, some careful route planning will overcome the problem of low torque/tractive effort.
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jamespetts

Does anyone have any idea of the correct amount of torque for the listed 'buses?
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ӔO

usually, for these types of diesel trucks and buses, the engines used have a lot of torque, but not a lot of power.
The problem of using real or realistic figures is that these things come with a fairly wide selection and it is compounded by the use of gears, because these things, particularly trucks, have a low range/crawler gear on top of their regular gearbox which multiplies figures depending on speed.

Looking at the specs of some popular trucks, ford f series and range rover, it seems like they have a minimum of 280 N·m in the 70's. Guesstimating how the engines were much larger, but older, for 1945 figures, I think we're looking at about 180 to 250 N·m. I would just keep in mind that I'm not an expert on engines or mechanics.
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jamespetts

Thank you very much for that - I shall have to look into integrating those figures. How do N·m convert to the KN used by the game?
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ӔO

I've looked into how to convert torque to tractive effort, and it seems like you need gear reduction ratio and tyre radius to figure it out. Which is similar to how you calculate TE for steam engines.
http://www.fordforums.com.au/showthread.php?t=104944
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jamespetts

Hmm - and how, I wonder, does one discover gear reduction ratios and tyre radii for 1940s 'buses?
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ӔO

some searching, and I found this site
http://www.routemaster.org.uk/index.php/the-bus/81-types

I think one would have to ask a mechanic or the maker to find out what tyre radii and gear ratio was actually used, but I don't think they will be too far off from what is currently used.
I'm not sure if this helps, but I also found a museum for transportation vehicles. http://www.eatm.org.uk/
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jamespetts

That page doesn't seem to have the crucial numbers, unfortunately. I could probably go to the London Transport Museum with a tape measure to get the wheel diameters, but how to get the gearbox data...?
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#11
IMO, gathering gearbox data could be a daunting to impossible task, because I think British manufacturers were rather creative in sourcing or creating parts for various batches.

I think it should just be a number that allows for a reasonable speed up an extended hill, like 15 to 20km/h for 1940's.
It's not unusual for heavily laden trucks of today to dip to 25km/h going up a steep and extended hill. Purpose built buses of today should be capable of 35km/h going up hill at the very least.
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Sholong

An additional observation: when the bus is going uphill with 4km/h, even if I change the bus's schedule, which made the bus to reverse and go downhill, the bus still keeps its 4km/h speed, until it run onto a flat road.