Quick Drive Physics

[JerryC]

I'm doing a little testing to try to get some locomotive physics closer to actual, and i've seen something odd about Quick Drive cars. Using two different trains:

Train 1 - U30C Southern Pacific, 10 regular load freight cars at 112 metric tons per. Effective HP per ton (excluding "parasitic" drain), is 2.3 HP per ton.

Train 2 - U30C Southern Pacific, 10 Quick Drive load freight cars at 112 metric tons per, same effective HP per ton.

Testing from Truckee to Summit on Donner Pass, on the 2.3% grade i'm pulling about 7mph with Train 1. I know that in real life the HP per ton is way low (3.2 - 3.5 is optimal) and that you would blow a DC traction motor or three doing that, but suffer with me for test sake. However, with Train 2, the train immediately stalls on the grade outside of Truckee. In order to get the same performance out of the QD loaded train, I have to reduce 45 tons from each car.

The difference between the regular load freight cars and the Quick Drive freight cars is this; the regular cars tonnage is split between 27 tons for the tare weight and 86 tons for the load. Now we know that in Quick Drive there is no option to load a car, so I have to fake the load by putting all of the weight in the tare.

[BNSFdude]

I'm almost certain a U30C would buck 10 loads up the extreme grades of Donner no problem.

[JerryC]

Using calculations that i've seen, and data from the "F59" post, i've been able to get the U30 close to what it is supposed to be when pulling those loads up that grade, around 11 mph. It's just weird that cars that are loaded via the tare act differently than cars loaded with tare and loads.

[BNSFdude]

It's a huge problem with open gondolas. The games physics freak out and make them behave very strangely.

[JerryC]

Ahhh, therein lies the problem, with making the car look like a heavy empty. But, the real problem here is that you cannot load a car in quick drive. Given all the other issues that are flagged when creating content for this game, I do not understand why DTG has not addressed this.

[BNSFdude]

Ahhh, therein lies the problem, with making the car look like a heavy empty. But, the real problem here is that you cannot load a car in quick drive. Given all the other issues that are flagged when creating content for this game, I do not understand why DTG has not addressed this.

They don't care to now. At least not until TSW is done.

[buzz456]

Or maybe no one has complained about this. I don't use QD all that much so never noticed.

[JerryC]

Personally, I don't like Quick Drive, as to me it "dumbs down" the simulation. But as with other things such as, and I find this hard to say ... lens flares ... if it's there, folks expect it to work correctly, so I try to be compliant and cover all the bases

[mjlevy1118]

Chiming in to say that while I have encountered no problems with Quick Drive physics, I exclusively run QD when I play Train Sim. I certainly appreciate the amount of time and effort that goes into creating enjoyable scripted scenarios, but to me, Quick Drive is vastly more flexible and replayable. The problem with pre-scripted scenarios is they're only enjoyable to play once, maybe twice, possibly three times if you're particularly dedicated. And you're playing a scenario in whatever weather, time, equipment, starting and stopping points that the scenario writer decided on. We all know how much of a PITA it can be to swap equipment in the current scenario editor if you don't have/don't like the DLC required for a particular activity.

Quick Drive is fun for me because I can play the game however I want, and I like being able to easily change the parameters for the drive and then hop in. I sincerely hope the option isn't lost in TSW. I do wish that there was a way to select your Quick Drive route, and the game automatically populates a stopping schedule (if you're driving passenger train) and allows you to edit it, kind of like MSTS used to do. In a perfect world, the game would generate AI services to breathe some life into the route without depending on the QD scenario writer to have thought of adding them in. Just my 2 cents.

[jalsina]

Quick Drive "always" runs all cars empty.
The sim is using the "mass" values to calculate car loads, but not the "cargo component".
112ton seems to me fully loaded cars (mass plus cargo).
I do use QD for a lot of my runs and this (empty cars) is the major handicap QD has.

[JerryC]

I'm supplying loaded quick drive cars that have the weight in the tare. The physics are different though because in order to make them equal in loaded "weight" to regular cars, the QD's are 45 tons lighter.

[jalsina]

I'm supplying loaded quick drive cars that .......

That can´t be in Quick Drive. Only the "mass" parameter will be considered to add up to the entire train weight. "Cargo component" (load) will not be considered.

[JerryC]

Go back and read my previous post again.