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Description of values for powerType, transmission, controlType of RS:propulsion [message #2223] Sun, 14 July 2019 06:37 Go to next message
Joerg von Lingen is currently offline  Joerg von Lingen
Messages: 118
Registered: May 2011
Senior Member
Dear all,

the wiki (https://wiki.railml.org/index.php?title=RS:propulsion) currently does
not contain a clear description of the enumeration values. Not in every case it
is really obvious. The technology development may also contribute in some more
variants.

powerType - the source of energy for propulsion of the vehicle
Currently we have [electric, diesel, steam] but what about new forms like
hybrids, fuel cell, battery etc?

transmission - the way to transmit and adjust the power to the drive
Currently we have [electric, hydraulic, mechanical]. Are there any other ways of
transmission?
Although not described in the wiki "hydraulic" stands for hydrodynamic and
hydrostatic transmission. The latter one is not really used for locomotive
traction why a discrimination would thought not necessary.

controlType - the way to control the power output of the traction drive
Currently we have [camshaftControl, contactorControl, rectifier,
thyristorControl]. Are there any other ways of control?

--
Best regards,
Joerg v. Lingen - Rollingstock Coordinator
Re: Description of values for powerType, transmission, controlType of RS:propulsion [message #2378 is a reply to message #2223] Mon, 09 March 2020 13:35 Go to previous messageGo to next message
Dirk Bräuer is currently offline  Dirk Bräuer
Messages: 279
Registered: August 2008
Senior Member
Dear Jörg,

from my point of view, and since nobody answered your post since more than half a year, I think this description of vehicle information is a bit too detailed for the current demand on railML.

> powerType - the source of energy for propulsion of the vehicle

Yes, we want to know something like that (I would not call it "source of energy" since there should not be any source of energy except possibly the big bang) but I cannot even exactly tell you why and what for we want to know that. In our software
- it gives the use a rough information rather for grouping engines,
- it switches some empiric formulas for entering new engines but that should have no relevance for railML.

So, it is rather a "weak" attribute. I would call it "main power supply" or "traction type" and I would currently provide [electric, diesel, gas, coal/coke, battery, hydrogen] as a "set of", so enumerable, to allow hybrids having more than one supply.

Steam is not a power supply but rather a transmission medium except for steam storing engines which are supplied with steam (instead of coal/coke) by an outside steam source. But steam may be acceptable as a synonym for coal/coke for backward compatibility.

It may be worth thinking about distinguishing between "electric-overhead", "electric-thirdRail" and "electric-battery" since any combination of these three kinds of supply is existing.

> transmission - the way to transmit and adjust the power to the drive

I agree with the definition but once more, we only need that for empiric formulas and this is possibly outside the scope of railML.

> Currently we have [electric, hydraulic, mechanical].

Here, steam should be available as a transmission medium from coal/coke to the wheels.
The problem is that there is no fixed border between the options: There are plenty of hydro-mechanic gears (starting converter + mechanical couplings in many modern small railcars, same technology as in street-cars with automatic gear) and there are even electro-mechanic hybrids at least imaginable (same technology as in some hybrid street-cars). So again, a "set of" (enumerable) would be necessary.

> Although not described in the wiki "hydraulic" stands for hydrodynamic and
> hydrostatic transmission. The latter one is not really used for locomotive
> traction why a discrimination would thought not necessary.

The latter is used for some maintenance vehicles and railway cranes which some customers really want to have in our software. But since all this is rather "nice to have", I don't think that we need to go more into details.

> controlType - the way to control the power output of the traction drive
> Currently we have [camshaftControl, contactorControl, rectifier,
> thyristorControl]. Are there any other ways of control?

Here we are at a place where I definitely want to jump off. I could describe how we encode the details of engine drives in our software, but I don't see any current demand for this in railML. For timetabling, the most important is to encode the traction force / tractive effort, the masses and in the last time, to go more into details of energy storing and recuperation and passenger services / features. So if you want to improve railML for vehicles, from my side I would think we should rather go in this direction.

Best regards,
Dirk.
Re: Description of values for powerType, transmission, controlType of RS:propulsion [message #2474 is a reply to message #2378] Sat, 27 June 2020 06:45 Go to previous message
Joerg von Lingen is currently offline  Joerg von Lingen
Messages: 118
Registered: May 2011
Senior Member
Dear Dirk,

thanks for your contribution but I don't want to start a philosophic discussion
about "creation" of energy.

PowerType stands for the kind of energy used to be transformed into kinetic
energy on the vehicle. And in that way "steam" is correct here.
There was a reason that many railways did encode the power type in their class
numbering system. It is because of the operational impact - use on particular
tracks, different speed profiles. In addition it might affect the rolling stock
rostering due to need for refueling etc.

The transmission and much more the controlType are more of interest, if one is
needing more details about the propulsion system itself, like for energy
consumption calculations.

Concluding that since the question was raised no real need for extension of the
existing enumerations were announced there won't be any changes in the schema.


Best regards,
Joerg v. Lingen - Rollingstock Coordinator
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