Starting a Y6B in Cab Mode

I am a total newbie to Trainz and having a blast driving my merchandise train down the New River Gorge towards Bluefield in the Appalachian Coal scenario. I sure hope that pesky switch at the Bluefield yard works when I eventually arrive.

I have found some interesting characteristics of driving the Norfolk and Western Mallet Y6B. When I start, especially on a grade, it does not like the Johnson bar in the full forward position. The regulator flashes yellow at me even when I open it up just a little and the train won't move; if I am on a grade the drivers eventually start to slip. When I move the Johnson bar back to the "company notch" at about 17% and apply a minimal amount of throttle, it seems to start much better. It also seems to start best if I throttle a little before the brakes discharge.

Is this expected? Does the regulator flashing yellow at me mean I am going to eventually slip? Have other people found different ways to get this monster going? Full forward Johnson bar and slowly opening throttle don't seem to be working for me, even with sanding.

Many thanks!

The yellow flashing means that the wheels are slipping. What you say is typical to the Y6B, wait till you are well on the way before increasing the reversor .
In that session you have to go easy otherwise you will run out of water and coal if you are too heavy on the regulator and reversor settings.

Thank you. Is that behavior due to the compound cylinders? Does the Big Boy behave differently?
Finally, what is a good running coal level for the Y6B. I spent most of the run at 10-20% coal which seemed low, but I kept my pressure up until I accidentally injected too much water and had to stop to rebuild steam.

Many of the steam locos have their own character , some that come from the same stable have the same specs and behave the same, but it is trial and error fun.
Generally between 65% and 70 % coal and water I find ok. It is better to feed small amounts of coal to the fireboxes and water to the boilers to keep good steam pressure .
It is actually quite realistic and works much the same as in real life.
One can also play and have fun with the locomotive physics settings like w/slip , sanding , coupler breakage values etc. in 'edit session' but that is deviating from the norm and can become unrealistic.