Proper Way To Measure Locomotive Wheels

We were supposed to cover this in engineer school, our instructor was nice enough to tell us what to expect from our Boss if and when we did screw up and they tryed to blame it on the speed of the train. He said he would show us the right way to measure wheels another day, well we all forgot to remind him. No im not in any trouble. Nothing has happened in quite awhile. LCJ?? G-A?? What would be the wrong way?

What type of wheel measurement, flat spots or flange?

Thinking back to my training, loco wheels have a 'witness' grove in them. I think the standard for most units is 40". You measure from the groove to the tread of the wheel, double it and add it to 40 for your diameter. I could be wrong on the 40" part though....

HEY thanks CN. I was "stepping off" the other night, half asleep, and i realized i never did find that out. Thanks buddy.