Yes, I removed the sliders. I've had no trouble with electrical pickup just using the wipers on the inside face of the wheels. I think it depends on how dirty or clean your track is (and mine is always dirty). As far as for tracking thru a turnout, there are some turnouts where the outside edge of the oversize flange, actually carries the weight of the locomotive thru the frog. I'm not really too familiar with all the manufactures and how their turnouts are designed. I use Gary Raymond metal wheels on all my rolling stock. They have a flange detail that is almost exactly like NWSL. From the looks of the picture above, it appears you are using Nickel Silver .250, is it MicroEngineering? I'd say the least expensive way to find out, is to order a set of scale wheels, install them on a piece of rolling stock and see how the scale flange tracks thru your turnouts. If you already have replaced the stock wheels on your rolling stock, and they don't derail all over the place, you should have no trouble with the locomotives. Good Luck
PS. 2 really nice CNW units. I've kitbashed some Aristo Evans boxcars to 1/32nd scale.Would you like me to post a picture of them?