I've fixed the pilots on all my engines now, and a huge difference it makes! I've also started addressing the gap between the lower part of the frame and tops of the truck sideframes. This involves using a piece of Plastruct ABS 2.4mm I-beam pieces. I've glued them to the frame, then repainted to match -you will also need to grind down the middle raised tab on the sideframes to allow room for the filler pieces. I've also added detail pieces to make it appear more realistic. I'm not done yet, but this is a start-