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Author Topic: Tram running costs  (Read 2174 times)

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Online Vladki

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Re: Tram running costs
« Reply #35 on: May 01, 2020, 06:27:53 PM »
Yes I have Czech source that says: https://www.zelpage.cz/clanky/pojednani-o-styku-kola-a-kolejnice?lang=en

At good conditions it can be 0.4, wet conditions even below 0.1. When designing adhesion brakes, 0.15 is assumed for safety reasons.
And indeed all trams I have checked so far are below this limit (normal, not emegrency brakes). I did not notice before that it is only about brakes. So yes, for tractive effort we may assume higher friction factor.

For T68, we know from some source that roughly 70% of their total weight is on powered axles, which means there is ~17% more weight on powered axled compared to the weight on unpowered axles.

If the weight would be equally split, it would be 66,6%, so it is only 3.33% extra, that is even less than the engine weight. Are you sure about the figures?


About CAF3 and similar. I think about removing the option to let them be in any config. Although you can order any combination, you cannot change it easily afterwards. (Yeah sending it back to the factory for overhaul and reassembly).
« Last Edit: May 01, 2020, 07:35:45 PM by Vladki »

Online Freahk

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Re: Tram running costs
« Reply #36 on: May 01, 2020, 08:05:27 PM »
Well, I might quote again from https://web.archive.org/web/20170411200128/http://www.lrta.org/Manchester/lrv_t68.html
Quote
Under full–load conditions almost 70% of the weight was on the powered bogies
I have no idea how reliable that source is but it sounds reasonable to me when looking at an image of T-68, specifically the position of the bogies.
Assuming evenly distributed weight along the car body, no weight at all would be on the jakobs bogie, if the other bogies were in the middle of each car body. Half the weight of the entire tram were on the jakobs bogie if the other bogies were placed under the end of each car.

If the weight would be equally split, it would be 66,6%, so it is only 3.33% extra, that is even less than the engine weight
17% more weight on powered axled compared to the weight on unpowered axles describes the ratio in between the axle load of these.
In numbers powerded_axle_load=unpowered_axle_load*1.17

That's not a factor between evenly distributed weight and mentioned 70% weight on powered axles.

Online Vladki

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Re: Tram running costs
« Reply #37 on: May 01, 2020, 08:49:28 PM »
OK, thanks for the explanation. In that case assuming evenly distributed weight, is not bad approximation. And we can assume that designers want to achieve that to keep the track wear minimal.

Online Freahk

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Re: Tram running costs
« Reply #38 on: May 03, 2020, 11:47:24 AM »
I just had a more-or-less detailled look at these changes.

Seems to be pretty good work!
In addition to the yesterday discussed points on stephenson-siemens, I have noticed that you seem to be using something like "weight=16,5" Wat does it mean?
Does not seem to be valid syntax for the weight to me, but I might be wrong.
Further, comfort and loading times might need some consideration but I don't think it's too important yet.

Is there any balancing formulate for these in the pak yet or are the current comfort and loading time values simply guessed?

A brainstorming of which factors will affect these in case we
loading times:
- number of passengers .
- number, better total width of doors
- door opening and closing times
- floor height/stairs (assuming stops are equipped with the optimal platform height)
- number of staff operating on the vehicle (tickets sold by driver)

Some of the above might also affect comfort.

comfort:
- type of seats
- acceleration bahavior (old vehicles tend to have a much more jerking acceleration)
- air conditioning

It will be hard to impossible to get fixed numbers for most of these variables, so guessing these and relating all vehicles to the same reference vehicle might be the best.

Online Vladki

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Re: Tram running costs
« Reply #39 on: May 03, 2020, 03:14:17 PM »
I have noticed that you seem to be using something like "weight=16,5" Wat does it mean?
Just 16.5... I have all the stuff in libreoffice and czech locales use comma as decimal separator. So it is just a typo or copy&paste.

Quote
Further, comfort and loading times might need some consideration but I don't think it's too important yet.
Is there any balancing formulate for these in the pak yet or are the current comfort and loading time values simply guessed?
I did not touch those. I'm not sure if I even want to dig that deep.

Just noticed that for midlands t69 , the intro was set to 4/1996 which is probably the time of building the first tram, but service started in 5/1999
Should I move it to 1999 or keep 1996 to fill the gap in timeline?
1992 - metrolink t68, sheffield supertram
1996 - midlands t69 ?
1998 - flexity swift
1999 - t68A + t69 ?
2004 - bombardier incentro

Online Freahk

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Re: Tram running costs
« Reply #40 on: May 03, 2020, 04:47:39 PM »
Difficult question that depends on a basic decision, which should then be consistent at least for all trams:
I see four (five) different candidate dates:
1. When the first unit from the vehicle family was produced (for use in Britain).
2. When the first vehicle was produced.
3. When the first vehicle gained permission to run.
4. When service actually started.

There is no clear best option. Imho the third should be preferred, but it's very difficult to get such data...
The first would be quite interessting if we introduce modular trams as you had planned with CAF Urbos.
Setups technically possible at some date will be available from the beginning on, even if not ordered that way in the UK. Technicaly improvements might be available as upgrades later on.
Second is a good compromise to the third as that kind of data is often available. It does, however not reflect testing of new vehicles and gaining permissions to run these, which in some cases can take several years.
The fourth point is not really an option imho.

Online Vladki

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Re: Tram running costs
« Reply #41 on: May 03, 2020, 05:17:00 PM »
In that case I will leave intro of t69 at 4/1996 (according to #2 start of production). And modify only the retire to 9/2014 when CAF3 entered service in midlands.

I found that wikipadia was copy pasting CAF3 info from edinburgh (7-car) to midlands (5-car). Not only the engine config, but also the weight.
It was susspicious that (5-car) caf3 would be so much heavier than other similar trams. I could not find exact accell info. Only here https://en.wikipedia.org/wiki/CAF_Urbos  they say it is 1.34. But without specifying which formation... However other specs are about 3-car formation so I can assume the same here. That would make 23.36 kN per bogie. If applying backwards to 7-car unit it will make acceleration 1.25 which is OK.
But we do not have the weight of the 5-car unit for midlands...

EDIT:
Well somehow sorted, and approximated.

Anyway the configurations are fixed. Especially because of the graphics, and different internal variations (seating). And a bug in graphics, the tram for edinburgh has the pantograph on wrong section.

Pushed to https://github.com/vladki77/simutrans-pak128.britain
« Last Edit: May 03, 2020, 08:36:44 PM by Vladki »

Online Vladki

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Re: Tram running costs
« Reply #42 on: May 08, 2020, 05:46:50 PM »
I have pushed final fixes for modern trams (since 1990) to https://github.com/jamespetts/simutrans-pak128.britain/pull/79


Online Vladki

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Re: Tram running costs
« Reply #43 on: May 11, 2020, 08:45:26 PM »
I noticed that the sheffield supertram (siemens-duevag) does not have real tractive effort. I could not find acceleration values for it. Can anyone help? According to wikipedia: Since its rail network includes gradients up to 10%, all vehicle axles are powered. So expectation can be high. Current value is 40 kN per bogie which is same as for T68. Both have similar weight (46 / 49 t) and similar power per bogie (277 / 240 kW). But duewag has 4 bogies (all powered), while t68 only 3 (and 2 of them powered). So in total duewag has more than 2x higher power and tractive effort. Is that OK to leave it as is?

Online Freahk

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Re: Tram running costs
« Reply #44 on: May 11, 2020, 11:36:58 PM »
I went across the web archives and found some data:
First, the capacity is wrong. It's currently 66 seats and 155 standing.
Quote
It can comfortably hold 88 seated and 162 standing passengers
However, later on in the sheeet the following is mentioned:
Quote
Passenger capacity 88 seated
155 standing at 4 passengers per m2
232 standing at 6 passengers per m2
The data we used for T68 assumed 4 passengers per m², so current standing capacity is fine but seating isn't.

Weight seems to be correct. According to the sheet it's 46.5t (empty)

Further,
Quote
Rated output 4 x 277 kW
Performance data Maximum acceleration: 1.3 m/s2
Maximum deceleration (service brake): 1.5 m/s2
Maximum emergency deceleration: 3 m/s2
So the power is fine, the force is not.

Source: http://web.archive.org/web/20160303170204/http://www.supertram.com/uploads/vehicleinfo.pdf
« Last Edit: May 12, 2020, 12:05:19 AM by Freahk »

Online Vladki

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Re: Tram running costs
« Reply #45 on: May 12, 2020, 03:38:46 PM »
Thanks for the link, capacity was clearly a mistake (wikipedia says 86 seats), forces calculated form acceleration. Pushed.

Online Vladki

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Re: Tram running costs
« Reply #46 on: May 13, 2020, 10:12:24 PM »
James, pleas incorporate:

https://github.com/vladki77/simutrans-pak128.britain/commit/d6299b622010d5a4bd3484675f8a7c89a23d1092

Also could you sync the tram dat files to simutranslator? There is one new tram (T68A) and a new part of CAF edinburgh (powered and unpowered bogie section)

Offline jamespetts

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Re: Tram running costs
« Reply #47 on: May 23, 2020, 04:22:04 PM »
This was merged a few days ago - my apologies for not noting this here sooner. Thank you for your work on this.

As to Simutranslator, I wonder whether it might be better for you to be given access to the pakset Simutranslator in your own right to make the necessary modifications? I believe that Makie is in charge of this now.

Online Vladki

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Re: Tram running costs
« Reply #48 on: May 23, 2020, 04:57:17 PM »
Maybe. I can make translations but I do not see (or cannot) upload dat files.

Offline jamespetts

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Re: Tram running costs
« Reply #49 on: May 23, 2020, 05:49:38 PM »
Maybe. I can make translations but I do not see (or cannot) upload dat files.

In that case, you need to be granted access as a pakset administrator, which would seem sensible in light of your very helpful contributions.