Stopping Stock Leaning

[maxtedrw]

Spontin sent me a message asking about my "fix" for leaning stock for RW2013 on the Talyllyn. I though I'd create a seperate post as its there for the future.

The reason stock leans seems to be the way the bogey pivot is set up. Bogeys have two pivots. The first pivot is the bogey itself rotating around an axis between the wheels. The second pivot is the rotation of the bogies as units relative to the centre of the coach.

For a 4 wheel stock (including trucks) this is of course one and the same thing but for bogey stock like the TR Bogey stock they are quite seperate items. This also applies to locos as well to some extent. An 0-4-0 is just a powered truck whereas an 0-4-2 is a sort of bogey coach.

So far as the pivots are concerned there are two kinds. Yaw ( side to side movement) is controlled by the X pivot i.e its a rotation looking down on the bogey. Roll ( or rotaion viewed end on from the back or front) is controlled by the Y pivot.


The key pararmeter is located in the <Bogey> section of the coach's .bin file ( not the bogey's .bin). This is the section which follows the line <SandFrictionMultiplier ...... So first you'll need to SERZ the .bin to make an xml to edit.

In the bogey section each bogey has a <BogeyPivotX > and a <BogeyPivotY> line. The X line tells where the bogey is located longitudinally relative to the coach centre and is its YAW pivot. The Y line specifies how high above the track top the roll centre of gravity for that bogey is located - this is the point about which the roll pivots.

In most of the TR coaches this is greater than 0. This is just like many standard gauge stock to ensure that they lean into curves as the Bogey has some springiness. For NG stock many of them have a roll centre nearly 0.5m above track top. This ( because the physics maths is designed for standard gauge stock) makes them tilt like anything on even quite ordinary NG radius curves.

Edit the line to read
<BogeyPivotY d:type="sFloat32" d:alt_encoding="0000000000000000" d:precision="string">0.0000</BogeyPivotY>

This will now anchor the stock to the track. This also works for locos as well to a greater or lesser extent.
Make sure you do this for each Bogey ( there are two sets of X and Y parameters ). ReSERZ to create a new.bin file and that should be it.

For the PPhorum stock this does not seem to be the whole answer yet - I am still getting the leans !!!

[spontin]

Thanks Richard
That seems to have done the trick for my Tom Rolt so working through the others and checking them.

Regards
Steve

[maxtedrw]

For the ProjectPhorum Coach stock there is an error in the bogeys - the centres X values do not match. One is about 8 something and the other 4 something - this is why even the fix above doesn't solve the "leans". By making both bogeys the LARGER value this solves the problem.

Tested all the TR stock - works on all of it