DT's light pacific 'bouncing'

[TheFlier]

Hi

having an odd problem with this engine.

example1
doing about 30-40mph - reverser at 35, regulator at 85. engine reaches a speed then refuses to go any faster, and the engine starts to gently bounce up and down. Then, without adjusting the regulator, I lower the reverser to 30 (from 35) and it stops bouncing and starts to accelerate again.

example2
doing about 40-50mph. reverser at 30, regulator ar 85. Accelerating ok. Leaving the reverser at 30, increase regulator from 85 to 100. Engine starts to bounce again, and speed starts to drop.


Those are the two problems, but they can happen at different speeds, with different reverser and regulator settings. It appears that certain combinations of reverser and regulator settings aren't compatible with each other at certain speeds.

I can't see this being normal behavior, but perhaps I'm wrong. Has anybody any idea what might be happening?

Thanks :)

[GaryG]

Completely normal action.

In the prototype, too much steam in the cylinder causes backpressure; at higher speeds the steam in the cylinder can't escape properly in the short time the exhaust port is open. On some locos, you even need to cut back on the throttle a bit as well to get to maximum speed. One hint, watch the steam chest pressure (I think that's what it's called in the sim). Try to keep it just at or a bit below maximum for optimum power (acceleration) at high speeds; this also tends to give the most efficient use of your steam as well.

This appears to be one part of steam physics that has been accounted for. I think there are tutorials about driving a steamer.

GaryG

[Machinist]

I'm not sure if is default or DLC, but there is a tutorial scenario named "3. Driving a Steam Locomotive with Expert Controls". Start TS2012 and then in the main page click in the "Tutorials" button. I never played, don't know how deep in details it goes...

[TheFlier]

ah :)

OK - thanks guys. It's just I never noticed it on other engines before.

[arizonachris]

Gonna have to learn to drive steam, my friend. 85% regulator is way too much. Drop both the reverser and regulator when speed flattens out. I usually run about 32% reverser and 40 to 45% regulator. You just have to fiddle with them to find the sweet spot. Takes a while, make 3 or 4 runs, you'll get the hang of it. Oh, and each and every steam engine is different in the way it drives. But they are all a blast (yes, pun intended) to drive.

[Machinist]

Dear The Flier,

Our Master Steam Engineer Mr. Chris (from Arizona) is all about driving steams! Do follow his guidelines and you will be faster and succesful! And also saving steam, I mean saving water and coal, which is always much appreciated by the Chief of Engineers of any railroad/railway.

[Kali]

Um, 85% regulator is not enough! open it all the way. If you've backed off to 15% reverser and you're still going too fast, then close it a bit ( I'd probably close it completely for a while at that point and then fully open again after a bit of slowing ), otherwise keep it wide open. If you find logs of real-life steam runs then the only time they're on partial regulator is the start when they're trying not to throw the fire away. Some two-valve regulators let you partially close without issues, but I think the RW code for that doesn't work...

Prototypically this is to stop you wire-drawing the steam and let what steam you have passed through expand properly in the cylinders and so do it's work fully. While it's good to drive prototypically in RW if you can, it also means you tend not to hit game engine limits like the back-pressure code.