Author Topic: Oil % Petrol accuracies  (Read 1790 times)

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Offline Spenk009

Oil % Petrol accuracies
« on: January 15, 2015, 03:57:24 PM »
In 1968, a new tank wagon is introduced with a problematic axle load. This got me thinking and calculating.  The tank wagon "BR TTA Air-braked Tanker" (filename: "wagon-tta") doesn't have tracks that are able support that weight until years later and those are the "premium" tracks. The weight of such a tanker filled with, bearing in mind the current density value, crude oil, it would weigh a total of 47t. On two axles. The same story is present in the older ("RCH Tanker wagon", wagon-tanker-rch) being too light in terms of axle weight (26t payload + 11t weight =/= 16t axle load).

So we are off with that axle load, but how do we calibrate realistic values? Searching Google, I found a site with a listing of relative densities of liquids. The interesting entries are: crude oil (790-973 kg/m³), fuel oil (890 kg/m³) and petrol/gasoline (≈724 kg/m³ for petrol and 832 kg/m³ for Diesel). The rough goods "Chemicals" are abstracted to simplify the game and 860 kg/m³ is probably a good approximation. Glad to find our current values taking differences into account, I do suggest that fuel oil be adjusted down to 900 kg/m³.

Thoughts on this?




Offline jamespetts

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Re: Oil % Petrol accuracies
« Reply #1 on: January 15, 2015, 10:13:46 PM »
The weight per unit of oil in the pakset is already set to 858kg. The TTA tanker wagon needed its axle load revising downward by 1t, as I think that I had calculated it on the basis of 1t/kl, but the rch tanker comes out at 16.6, so I have amended it by rounding it up to 17.

Thank you for your research!
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Offline Spenk009

Re: Oil % Petrol accuracies
« Reply #2 on: January 16, 2015, 11:49:14 AM »
I made a huge error in the first post. The year is 1964! I'm not sure what happened and led me to that, when I checked in on August 1968 I found everything well organised.

I'd suggesta reduction of 2t (down to 20t), on the basis that during introduction there are no rails these coaches run on. 20t is the maximum axle load available on any rail and in January 1965, this rail type disappears (leaving 17t and 19t). Only in March 1968 does a 22t heavy get introduced. August 1968 finally sees a 20t steel type being released which costs a fraction of the other rails in monthly maintenance.

This is a three year span in which an unprepared/inexperienced player has no option to make any rolling stock increases in terms of rail. If he chooses to upgrade the part of the "oil" network, he may be unable to finish before January 1965 and is then stuck. Should the introduction of the rails be hastened or the tankers delayed? Is it possible to add intermediate coaches to the game that increase speeds to ~80km/h?

Slightly off-topic: Why does the BR TEA Bogie Tanker have a top speed of 96km/h if its predecessor was able to achieve 120km/h? It could appear that the two speeds are reversed in this case.

Offline jamespetts

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Re: Oil % Petrol accuracies
« Reply #3 on: January 16, 2015, 10:33:31 PM »
The 109lb/yard track is introduced in 1925 and is capable of up to 22t, so this should not be a problem (I cannot remember whether this is in the released version 0.9.1, or is new to the development version on my Github repository).

I have reduced the speed of the TTA wagon to 96km/h: I suspect that both originally had the 120km/h speed, and the TEA wagon had the maximum speed reduced following research, which I forgot to apply to the TTA.

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Offline Spenk009

Re: Oil % Petrol accuracies
« Reply #4 on: January 17, 2015, 05:23:29 PM »
The 109lb/yard track is not available at the time in 0.9.1. It's probably only on GitHub.

Someone agrees with the limit here.

I guess we've resolved the topic then.

Offline jamespetts

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Re: Oil % Petrol accuracies
« Reply #5 on: January 17, 2015, 07:36:02 PM »
Splendid - thank you for checking.
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