09:09 Feb 19, 2009 

@conny: that how I too see it. On a nitpicking note: "without loss" is not strictly correct as you'll have conversion losses (eta of about 95%). But basically you get back what you had to put in. Best.

17:54 Feb 18, 2009 

es sind auch keine weiteren Angaben dazu im Text vorhanden, nur dieser eine Satz. Da es sich hier aber um Züge handelt, erscheint mir die Erklärung im Link von efreitag zu den Modellbahnen schlüssig :
Grade Resistance
Resistance that results from the energy you must put into a train to lift it vertically. The energy is returned without loss when the train comes back down again.

10:06 Feb 18, 2009 

...if you go uphill or downhill, it's just like efreitag has explained - the force is always the same.

09:12 Feb 18, 2009 

@hazmatgerman: Yes, I know what you mean, but it's always the same force acting in the same direction (downhill), no matter whether you go uphill or downhill. If you go uphill, it decelerates, if you go downhill, it accelerates ;-) Have a nice day!

09:08 Feb 18, 2009 

@efreitag: both ways because source texte refers to Gefällstrecken and bergauf which is both ways, isn't it? As the Beschreibung is directed to professionals I second grade resistance. Best to you and Cox.

09:01 Feb 18, 2009 

Agree with hazmattgerman & efreitag; IMO it depends on the readership. For railway engineers, 'grade resistance' may be better, but for general readers 'downhill force' or (even) 'force of gravity' would be better, as they are unlikely to know what 'grade resistance' means.

08:52 Feb 18, 2009 

Anyway, this is splitting hairs: In the given context (no actual values), "force of gravity" will probably work just as well.

08:49 Feb 18, 2009 

Just for the books: The German term "Hangabtriebskraft" is clearly defined as a vector pointing in the direction of travel (hence orthogonal to the normal force), as harmatgerman says, so it is not the same as the force of gravity, but resulting from it.

08:41 Feb 18, 2009 

Sorry for asking: does your context say whether they are talking about the vertical vector or specifically about the resultant force acting in/against the direction of travel? Only the latter can be utilized as described IMO.