The total force required to move the train form rest?

Question

What is the total force required to move the train form rest? Can anybody write down some mathematical formulea?

Answer 1

When the wheels slip, back it off a notch.

Answer 2

Indeed there is a formula.  

But, you have me at a disadvantage, as I cannot remember it off hand.  I remember there is a multiplier of 20 or 30 in the equation, depending on circumstance, but I haven't used it since I was an instructor.

It is similar to the rolling train resistance formula, which I have given here many times, but rather than yielding speed it enumerates factors in the loading capability of the draft gear, in particular the psi relative to the area of the knuckle face, not to exceed 240,000 psi.  

I will find it in my stuff however, and edit in a day or two.  The hardest part is finding it.  There's lots of stuff.

Rarely am I at a loss for words.  My apologies..............

By the way.  Your first question is an excellent one.

Addendum:  Day two and still looking. It may be in a box of stuff I sent to one of my kids.  If the question expires and I haven't yet found it, send me some contact info and I'll get it to you when I can.  I know I have it somewhere.