[Genma Saotome]

Ed, does this change mean the multiple models of this locomotive can be merged into one?

Right now they're a .wag and an .eng and with four units in a typical lashup OR doesn't "register" them as a single unit for pumping up the brake line. makes it a bit dangerous to run in the mountainous territory where they were used.

[edwardk]

Genma Saotome, on 15 July 2018 - 03:40 PM, said:

Ed, does this change mean the multiple models of this locomotive can be merged into one?

Right now they're a .wag and an .eng and with four units in a typical lashup OR doesn't "register" them as a single unit for pumping up the brake line. makes it a bit dangerous to run in the mountainous territory where they were used.

Extensive testing would have to be done on your part since the change I did was to officially tell OR that more wheels and bogies should be recognized. This of course is based on the exact naming of the items.

[Traindude]

My apologies for bumping this thread, but while we are discussing possible ways to allow for complex locomotive and rolling stock models, I have been wondering if any allowance can be made for deviation from the "traditional" MSTS-style hierarchy structure to, for example, convincingly simulate large articulated steam locomotives.

Here is an example of how I'm thinking the original MSTS hierarchy format could be modified for a 4-6-6-4 "Challenger"-type articulated steam locomotive.
https://i.ibb.co/v1kSrrz/orartic.png

In this case, instead of having the "MAIN" part of the shape file function as the whole locomotive chassis, "MAIN" serves as the frame's hinge pin and is used to establish the articulation point between the two halves of the chassis. The two halves, respectively labelled "CHASSIS_FRONT" and "CHASSIS_REAR", are parented to "MAIN" and are allowed to independently pivot about the point established by "MAIN", relative to track conditions such as curvature.

With the chassis broken down in this manner, it is possible to parent wheels, bogies and other parts to their corresponding chassis halves instead of parenting them to "MAIN" like on a rigid-frame locomotive. Thus the front bogie, the front group of driving wheels and other parts associated with the front chassis (front coupler, pilot/cowcatcher, headlight*, etc.) would be parented to "CHASSIS_FRONT" instead of "MAIN". Likewise, the rear group of driving wheels, rear bogie and other parts associated with the rear chassis (cab, boiler, etc.) would be parented to "CHASSIS_REAR" instead of "MAIN".

*Some articulated locomotives, mainly logging Mallets, have their headlights mounted on the smokebox rather than the front chassis pilot deck. In this case the headlight would be parented to "CHASSIS_REAR" instead of "CHASSIS_FRONT". (Which reminds me that there needs to be some way to assign lighting and smoke/steam emitter coordinates to the respective halves of the chassis so they follow that half of the chasis on curves...but for now that can wait...)

For now I am just thinking out loud. But this begs the following question: What would it take to modify the OR code to allow for modified hierarchies such as this?

[Genma Saotome]

It would be good to see some progress on this issue.

Question: IN the problem you cited, why put the headlight on the read chassis? That chassis rotates too. Shouldn't it be left in main?

[Traindude]

Genma Saotome, on 18 September 2020 - 01:19 PM, said:

It would be good to see some progress on this issue.

Question: IN the problem you cited, why put the headlight on the read chassis? That chassis rotates too. Shouldn't it be left in main?

Keep in mind that the boiler (including the smokebox) is rigidly attached to the rear chassis. Thus if the headlight were mounted of the boiler front instead of on the front chassis just above the pilot, it would thus technically be attached to the rear chassis and consequently, when the locomotive enters a curve, the headlight pivots in sync with the rear chassis once the rear group of driving wheels enters the curve. Likewise, if the headlight were mounted on the front chassis, it would pivot in sync with the front chassis when the front group of driving wheels enters the curve. It stands to reason that parenting parts to only one half of the chassis instead of "MAIN" would cause the part to pivot in sync with that specific half of the frame.

Let me try to clarify the function of "MAIN" in my design: In this modified hierarchy, instead of "MAIN" serving as the whole locomotive chassis (like on a rigid frame engine), it serves as the hinge between the front and rear halves of the chassis.

However, here's a drawing showing how the cone of the headlight moves relative to the chassis halves when the locomotive enters a curve:
https://i.ibb.co/28gV64D/articcurve.png

The drawing suggests that you were correct in thinking that the "MAIN" part could theoretically be the whole rear chassis, and not just the hinge pin. But then again, I sort of overlooked this when I was designing my hierarchy.