The NEW Walthers/LifeLike N-scale locos are great! Split frame design,Great detail,And the latest run of GP38-2's are DCC ready. A list of them is GP18's(split frame design) GP20's,GP60's,GP38-2's(Latest run) These are all great running and great looking Locos.
Here's a N-scale BNSF Remote control equipped unit I did awhile back with scratch built antenna stands andwire grabs and such. Now in service in the UK somewhere.
And one of my older projects SP SD40R with cut levers and weathered to match the prototype
Union Pacific C44-9W #9819 plus two other lead units head downgrade with howling dynamic brakes while two other DPU units help to bring this 7500 ton manifest safley into LaGrande, Oregon.
This is all Terminal 6 in Portland, OR. There's Oregon Steel Mill, A potash facility, multiple container yards/storage,A few Grain loading facilities,at least two autorack loading yards. Oh! Yeah and A BNSF yard(Maybe it's Lake yard? Not sure.)
Unless there is a huge difference in speed it won't really matter too much. After the GP40-2 breaks in it will run closer to the same speed.
The only time that speed difference is an issue, is when you have an older Atlas with a newer one with the slow motor.
I think these standards apply to actual flags. As you stated this is an image of the flag.
I think UP tries to keep these things clean,But most of the CTE's end up at the back of the train in DPU service therefore do not stay clean long!
This is what I found on Wikipedia...