A shot taken from underneath the chassis before the cogs were firmly located on pins or axles. Front is to the right of the photo. The right side of the loco is at the top of the photo. Use long nosed pliers to hold the axle by one end, and place it in the hole just enough to hold it in position. With a light, look at the cog though the axle hole from the other side. Use the pin to make sure that they are aligned, and then firmly push the axle though.