Articulated Stacks

[_o_OOOO_oo-Kanawha]

The cars are still in beta, because the physics need still some sorting out.

I have redistributed the empty weight, loading the "W" truck, which makes it less prone to derailments.
Tare weight of a 5 unit set is 177.200 Lbs, max loaded weight is 800.500 Lbs.
Figures are arbitrary, 5 cars of 35.440 Lbs kg or 5 empty cars of 20.000 lbs and 4 "W" trucks of 19.300 Lbs.
Unfortunately, without scripting, the "W" truck will not carry its share of the lading.
So the proposal of fixed unloaded and loaded sets is perhaps the best solution.

I've made up testing consist of 20 sets, 3 ES44AC's up front, 2 DPU at the rear. And a 30 sets consist: 3 ES44AC's up front, 20 sets, 2 DPU's, 10 sets, 1 DPU at the rear.

Running these over Sherman Hill, Soldiers Pass and Cajon Pass gives quite realistic handling IMO, and the consist doesn't derail when going into emergency. Still, the "W" truck tilts a little under strain.
However, such long consists have a tendency to break apart after a while. The train doesn't go into emergency, just leaves part of it behind.

[dtrainBNSF1]

So far I've only been running the set in forward motion - never thought about trying them in reverse. In my own application I've mixed them into a 96-car consist with the 5-car set and the other G-Trax Husky Stacks - they all look quite handsome and realistic in one consist. Power consisted of 5 Gevos on the head end going over Cajon Pass.

I'll do some more tests with these stacks in the near future.

[ricksan]

Hi all. Thanks for your feedback. This is a tough one, isn't it! We can certainly use some articulated stacks for our modern routes, but I'm hesitant to release something and call it "final" until together we can solve the problems you've reported. The articulateds are in a holding pattern for a few more days while your testing reports continue come in and while I help put the finishing touches on a certain "other" project. What project? We'll find out soon enough, but if you look at the screen shots I posted in this thread, maybe there's a clue.

Anyway, there have been some further developments at this end. I made three more sets in the following liveries: BNSF swoosh, TTX with old logo, TTX new logo. Also, another guy and I have been exchanging emails offline regarding an alternate way to set up this kind of consist. Nothing definite yet, but when I resume working on the Maxi-Stacks I'll try out his idea. If it works OK I'll submit a new beta and see if that one fares any better.

Regarding the Quick Drive question, the final product will include a consist blueprint for each of the four sets. Those consists will show up in the scenario editor so you can select and drop them onto the tracks. You can make your own, custom QD consists using RW_Tools or by editing your own consist and consist-fragment blueprints.

[dejoh]

I think I see the Chicago Skyline.

[_o_OOOO_oo-Kanawha]

Hi all. Thanks for your feedback. This is a tough one, isn't it! We can certainly use some articulated stacks for our modern routes, but I'm hesitant to release something and call it "final" until together we can solve the problems you've reported. The articulateds are in a holding pattern for a few more days while your testing reports continue come in and while I help put the finishing touches on a certain "other" project. What project? We'll find out soon enough, but if you look at the screen shots I posted in this thread, maybe there's a clue.

Anyway, there have been some further developments at this end. I made three more sets in the following liveries: BNSF swoosh, TTX with old logo, TTX new logo. Also, another guy and I have been exchanging emails offline regarding an alternate way to set up this kind of consist. Nothing definite yet, but when I resume working on the Maxi-Stacks I'll try out his idea. If it works OK I'll submit a new beta and see if that one fares any better.

Regarding the Quick Drive question, the final product will include a consist blueprint for each of the four sets. Those consists will show up in the scenario editor so you can select and drop them onto the tracks. You can make your own, custom QD consists using RW_Tools or by editing your own consist and consist-fragment blueprints.

They are indeed tricky cars! My 30 sets train again broke apart going uphill near Lugo, but is now decending the infamous Cajon Pass 3.4% grade. With 10 PSI reduction and 50% dynamic braking of the 6 ES44AC's, I am able to maintain a nice and even 15 MpH. Throwing the train into emergency didn't make it to slow down at first, only very slowly after a while. So, what about the brakes? The TOB figure: Tons per Operative Brake, a 800000 pounds five car set rides on 6 trucks, each individualle braked in the prototype, or 133333 pounds per operative brake.
According to the BNSF SSI the 5 unit set counts as 3 cars, so a fully loaded set will have a TOB of 266666 or 133 US Tons? This is at the limits for the Cajon Sub. For this TOB, California Division BNSF timetable lists a max speed of 45 MpH overall and 20 MpH going down w/o DPU or 25 MpH w DPU with at least 60 axles of dynamic braking, a ES44DC counts as 8, ES44AC as 10 axles of dynamic braking. Any less axles and the retainers will have to be used.

How to alter the braking parameters to have this car braking properly? The "W" trucks don't have any braking in the beta, perhaps its best to divide the braking over the cars and 'W" trucks, so there remain 6 actual brakes in operation?

I noticed there are no handbrakes defined, so I'll copy that section over from some other double stack car. It's always nice to have strong handbrakes as the train in full emergency finally came to a stop but still slowly creeps down the 2.2% grade. There are only handbrakes on the A and B cars?