Aristocraft Dash 9's

[ort11]

Have been in the hobby for a bit and just acquired 2 used Dash 9's. They are in good shape. The one thing that I am noticing that one is pulling about 20-25% less than the other. Are there any adjustments / lubrication / reasons for this difference? Thanks in advance

 

[spike]

Rolling stockwise or speed wise?
If it's pulling less rolling stock open both fuel tanks and see how many lead bricks
are in each. Dash 9s have room for a total of 3 bricks but normally come with one
fitted.
I have 4 Dash 9s and they do vary slightly in speed but I believe it's not by anywhere
near 20%, most locos tend to have a slight speed difference.
Check the wheels are really clean as power only comes thru the wheels and the do get dirty
quite quickly.
Check that all four motors are actually working, there are two per truck.