Freight Animation

After the recent problems encountered with Open Rails when using a Freight Animation (FA) in a tender to place the loco crew on the footplate, I thought I'd try and solve the one main question I had.  Checking all the documentation available on the internet together with trawling the UKTS and trainsim.com Forums and not finding the answer, I did some testing myself.

My question was :- Why are there sometimes three parameters after the shape file name and at other times, only two?
The documentation I found gave the first as the shape's starting position, in metres, relative to its origin and the second as it's final position, again in metres, relative to its origin.  There is no general mention of a third parameter, except in the odd Forum post, where it has been called "step".

In my tests, I have discovered that Freight Animations are treated differently for tenders than for other vehicles.

Tenders
First numeric parameter       : Shape starting position relative to its origin, in metres
Second numeric parameter : Final position of shape, relative to its origin, in metres.
Third numeric parameter     : set to any positive value, or omitted, causes the shape to drop - see below.
As long as the second parameter is lower than the first and the third parameter is either omitted or has a non-zero value, the shape will drop, as long as the consist is moving.  It doesn't seem to be based on the distance travelled.
If the second parameter is not lower than the first, no movement will take place irrespective of the 3rd parameter.
The value entered as the third parameter doesn't seem to have any effect on the rate that the shape moves down, but needs a great deal more testing to be certain.

Numeric values of zero,eg ( 8F.s 0.0 0.0 0 ) is valid, and it's not necessary to show decimal points - may be ( 8F.s 0 0 0 )

ODD fact : If the first parameter has a negative value, to place it below its origin, and the third parameter is either omitted, or has a non-zero value, the shape will rise, presumably to it's original position, irrespective of the value in the second parameter.  I can't think of a use for this, but no doubt, somebody will!!

Other Vehicles
First numeric parameter       : Not used, but must be present as a "place-holder" for the second parameter.
Second numeric parameter : Must be any non-zero value - has no effect on position, but if zero, the shape doesn't show.
Third numeric parameter     : Not used.

Conclusion
I discovered why some FAs have two and others have three parameters; also, that some which have three only need two, eg 8F.s 0 3.0 0.0 could be 8F.s 0 3.0, 8F.s 0 1, or even 8F.s 0 0.  In those examples, the 2nd parameter is NOT less than the first, so no movement will occur and the 3rd can be omitted, even though it defaults to a positive value.

Hi All,
This bug was reported as being corrected in R2618, but on testing it I found that, if anything, the situation was worse!! The normal action should probably have been to submit a report to the Team, but I decided to investigate further. First, may I refer you to a report of my findings on using Freight Animations which I posted earlier this year (See post above). In that report I queried the use of the second parameter after the shape file name, in the FA line in the eng file, eg FreightAnim ( 8F.s 0 3.0 0.0 ) when used for placing crew on the loco footplate. Based on my tests when preparing that report, I amended the 3.0 to 0.0 - this resulted in the crew being shown correctly when using the latest version of Open Rails, but what's more important is that MSTS still shows the crew correctly. This begs the question - Where did the use of 3.0 as the second numeric parameter come from, and why?

Note that the second and third numeric parameters ARE used when a Freight Animation is used to vary the position of the fuel load over a journey.

I have checked a dozen locos from the UKTS library which use a tender FA to place crew on the loco footplate and they all have 3.0 as the second numeric parameter. Of those, I selected 6 to test using MSTS and latest Supporters' version of OR, with both 3.0 and 0.0 as the second parameter. MSTS showed no difference, as far as I could tell, between the use of 3.0 and 0.0. Using OR, and value 3.0, there was no fixed position for the crew to appear (in one loco they were standing on top of the coal, whereas in another they were well forward of the smokebox door), but changing it to 0.0, the crew appeared correctly on the footplate in all cases. As an additional test, I ran an earlier version of OR (Aug 2014) with 0.0 as the parameter, and in all cases, the crew weren't on the footplate.

Following these results, I am reluctant to report that the problem hasn't been solved as it seems to be due to a spurious parameter value which has a dubious origin and/or purpose.
I would be interested to hear the opinions of other members regarding the direction to take in this matter